I really enjoy Sam Newman's writing and conference talks about microservices. This book is a great resource for the myriad challenges encountered during monolith decomposition.

Despite the niche-sounding title, this book is a fantastic resource for understanding engineering practices that enable engineers to create and maintain high quality software.

I really enjoyed the detailed exploration of cultural topics like knowledge sharing and leadership, as well as technical considerations of various types of testing, static code analysis, and dependency management. Highly recommended book for mid- to senior-level software engineers and managers looking to gain a well-rounded understanding of the scope and depth of the practices and tradeoffs in modern, quality-focused software engineering.

Pretty interesting resource overall, but probably best to simply read the same material from Larson's blog, StaffEng, which contains a collection of stories with many "staff-plus" engineers.

Alan Lightman explores the tensions and congruences between conscious experience, religion, and a scientific understanding of reality as a materialist.

I've listened to a handful of titles from The Great Courses - this series from 2004 is among the best I've found. John McWhorter takes the listener on a broad tour of the study of language, including prominent language families, how language changes over time, and how dialects, pidgins, and creoles emerge. McWhorter infuses humor and personal anecdotes with the lecture material, creating an engaging and thoughtful overview of natural language.

I loved this collection of poetry and correspondence.

See also: The Atlantic in 1891: Emily Dickinson's Letters

Dear friend, I think of you so wholly that I cannot resist to write again, to ask if you are safe? Danger is not at first, for then we are unconscious, but in the after - slower - Days - Do not try to be saved - but let Redemption find you - as it certainly will - Love is it's own rescue, for we-at our supremest, are but it's trembling Emblems -

Your scholar -

Emily Dickinson, letter to Thomas Wentworth Higginson, 1863

An engaging high-level tour of typical problems, solutions, and the associated trade-offs that occur any system that writes, reads, updates, and deletes data. Reads a bit like an almanac of software patterns and specific implementations used in practice, which I found very enjoyable. Covers a wide range of topics, including storage and retrieval, OLTP and OLAP, replication and partitioning, distributed transactions, 2PC, consistency and consensus, and batch and stream processing. An ideal introduction to common database patterns and distributed systems.

I picked this up more or less by chance, though it was an interesting choice in the sense that it reflected an intersection of the ideas Nietzche and Jung during a period when I am deeply fascinated by Jung and had just listened to a Great Courses series on Nietzche. Generally fascinating, though not entirely resonant with my developing perspective on the topic of self-will that has occupied a lot of space in my thoughts recently.

"One never reaches home," she said. "But where paths that have an affinity for each other intersect, the whole world looks like home, for a time."

"I wanted only to live in accord with the promptings which came from my true self. Why was that so very difficult?"

I continue to read Eknath Easwaran, as I really enjoy his approach to communicating ideas about love and selflessness present throughout the world's religious texts, particulary the Bhagavid Gita and the gospels. He often draws upon wisdom imparted to him as child in southern India by his grandmother. In this book, he reflects on the 8 Beatitudes of Jesus' Sermon on the Mount. His stories and reflections also draw upon writing from the contemplative Christian tradition, including John of the Cross, Meister Eckhart, Teresa of Avila, Thomas à Kempis, and Thomas Merton.

"He that loveth not, knoweth not God;", says John the Apostle, "for God is love." The words sound so ethereal that most of us cannot connect them with daily life. What, we ask, do personal relationships have to do with the divine? I would reply, it is by discovering the unity between ourselves and others - all others - that we find our unity with God. That is why training the mind is the nuts and bolts of religion. We don't first get to know God and then, by some miracle of grace, come to love our fellow human beings. Loving comes first: learning to love others is how we move closer to the Lord. In this sense, learning to love is practicing religion. Those who can put the welfare of others before their own small personal interests are religious, even if they would deny it. And, of course, anyone who can quote scripture chapter and verse but will not put herself out for others has yet to learn what religion means.

Most of us, as my grandmother once told me bluntly, confuse self-pity and grief. Granny was as tough as she was loving. When I would come to her crying because my feelings were hurt, she could be terribly unsympathetic. "That's not grief." she would say. "You're just feeling sorry for yourself." Self-pity weakens us; grief, which means sorrow for others, ennobles us and releases inner resources to help.

Just finished “The Soul of a New Machine,” a book I added to the reading list after noticing it on Joe’s desk at the end of HCF. After hearing Bryan Cantrill mention the book in more than one talk, I decided to bump it to the top of the list. The book won the Pulitzer for nonfiction in 1982, and tells the story of two groups of engineers at Data General, one group in North Carolina who were tasked with building a computer to compete with Digital Equipment Corporation, and a group led by the central figure in the book, Tom West, at Data General’s headquarters in MA. West starts a skunkworks project as a backup to the product under development at North Carolina’s lab. Due to failures at NC, West’s project soon becomes critical to the success of Data General. The author embedded himself with various members of the team - many of whom who had just graduated college, had little experience, and essentially lived at work - during an intense period of delivering an early 32-bit microcomputer to market. This book captures the atmosphere of small-team work in the then-emerging microcomputer industry. This book has caused me to reflect on my own experience in software, and, for the first time, contextualize it to a degree within a larger story - one I didn’t know much about. Many of the engineers in the book, now speaking 40 years ago, talk about the attraction to the work, its problems, the artfulness of the practice, in ways that feel familiar. From hunting bugs (there is an example of two engineers debugging a race condition in hardware described towards the end of the book), cutting corners to “get something out the door,” to burnout, this book resonated with the professional aspect of my life in a way I haven’t previously encountered in text. I wish I could have coffee with these folks.

This is an absolutely beautiful reflection on the relationship between person and landscape. Nan Shepherd writes about her experience exploring the Cairngorm mountains in the Scottish highlands. She writes with a sincere sense of wonder and humility in light of the mystery and power of the mountains. I listened and re-listened to this book in audio format on walks through the woods on the weekends and was enthralled with the text from beginning to end.

Wendell Berry is at the top of the list of writers whom I deeply admire and whose writing consistently changes the way I think about things. Several of my favorite essays from this collection include "A Native Hill" and "Think Little." "Think Little" in particular echoes throughout my thoughts this year. If you've found your way to my half-baked reading notes looking for something to read that might have perspective-altering consequences, I could recommend nothing better than this collection of essays.

The difference between a path and a road is not only the obvious one. A path is little more than a habit that comes with knowledge of a place. It sort of ritual of familiarity. As a form, it is a form of contact with a known landscape. It is not destructive. It is the perfect adaptation, through experience and familiarity, of movement to place; it obeys the natural contours; such obstacles as it meets it goes around. A road, on the other hand, even the primitive road, embodies a resistance against the landscape. Its reason is not simply the necessity for movement, but haste. Its wish is to avoid contact with the landscape; it seeks so far as possible to go over the country, rather t through it; its aspiration, as we see dearly in the example of our modem ways, is to be a bridge; its tendency is to translate place into space in order traverse it with the least effort. It is destructive, seeking to remove or destroy all obstacles in its way. The primitive road advanced by the destruction of forest; modern roads advance by the destruction of topography. (Wendell Berry, “A Native Hill”)

Famous 14th century text on contemplative prayer

"And so I urge you, go after experience rather than knowledge. On account of pride, knowledge may often deceive you, but this gentle, loving affection will not deceive you. Knowledge tends to breed conceit, but love builds. Knowledge is full of labor, but love, full of rest."

One of the earliest books of the English language known to have been written by a woman. I listened to an audio recording of this book this year as I continue an exploration of theological works related to the contemplative Christian tradition.

A beautiful book about living in mindfulness. If you're interested in learning about the practice of mindulness and compassion, I would highly recommend this book.

I see that I am like a wave on the surface of the ocean. I see myself in all the other waves, and I see all the other waves in me. The manifestation or the disappearance of the waves does not lessen the presence of the ocean."

One of my favorite collections of nature writing. I listened to this collection of essays on audio book recently on several walks at Lake Kegonsa and Governor Nelson state parks.

These essays are an engaging patchwork of observations about the beauty of the vast landscapes of the American West, encounters with other people, animals, and plants in the wilderness, and praise of the cleansing and invigorating power of being alone and immersed in the wild.

Muir weaves a certain sense of awe through his writing from his "being-in" nature, sometimes expressing seemingly numinous experiences. However, rather than reflecting deeply inward or attempting to navigate the meaning of such events, he remains grounded; he points to the source. There is an interesting contrast between Muir and Emerson here that I would like to explore sometime.

I smile each time Muir implores his imagined reader to leave town and seek such outings.

Walk away quietly in any direction and taste the freedom of the mountaineer. Camp out among the grass and gentians of glacier meadows, in craggy garden nooks full of Nature's darlings. Climb the mountains and get their good tidings. Nature's peace will flow into you as sunshine flows into trees. The winds will blow their own freshness into you, and the storms their energy, while cares will drop off like autumn leaves. As age comes on, one source of enjoyment after another is closed, but Nature's sources never fail. Like a generous host, she offers here brimming cups in endless variety, served in a grand hall, the sky its ceiling, the mountains its walls, decorated with glorious paintings and enlivened with bands of music ever playing. The petty discomforts that beset the awkward guest, the unskilled camper, are quickly forgotten, while all that is precious remains. Fears vanish as soon as one is fairly free in the wilderness.
(John Muir, "The Yellowstone National Park")

One of my favorite essays from the collection is "A Near View of the High Sierra"

Now came the solemn, silent evening. Long, blue, spiky shadows crept out across the snow-fields, while a rosy glow, at first scarce discernible, gradually deepened and suffused every mountain-top, flushing the glaciers and the harsh crags above them. This was the alpenglow, to me one of the most impressive of all the terrestrial manifestations of God. At the touch of this divine light, the mountains seemed to kindle to a rapt, religious consciousness, and stood hushed and waiting like devout worshipers. Just before the alpenglow began to fade, two crimson clouds came streaming across
the summit like wings of flame, rendering the sublime scene yet more impressive; then came darkness and the stars.

How still the woods seem from here, yet how lively a stir the hidden animals are making; digging, gnawing, biting, eyes shining, at work and play, getting food, rearing young, roving through the underbrush, climbing the rocks, wading solitary marshes, tracing the banks of the lakes and streams! Insect swarms are dancing in the sunbeams, burrowing in the ground, diving, swimming,--a cloud of witnesses telling Nature's joy. The plants are as busy as the animals, every cell in a swirl of enjoyment, humming like a hive, singing the old new song of creation. (John Muir, "The Yellowstone National Park")

Now comes the gloaming. The alpenglow is fading into earthy, murky gloom, but do not let your town habits draw you away to the hotel. Stay on this good fire-mountain and spend the night among the stars. Watch their glorious bloom until the dawn, and get one more baptism of light. Then, with fresh heart, go down to your work, and whatever your fate, under whatever ignorance or knowledge you may afterward chance to suffer, you will remember these fine, wild views, and look back with joy to your wanderings in the blessed old Yellowstone Wonderland. (John Muir, "The Yellowstone National Park")

It may be asked, What have mountains fifty or a hundred miles away to do with Twenty Hill Hollow? To lovers of the wild, these mountains are not a hundred miles away. Their spiritual power and the goodness of the sky make them near, as a circle of friends. They rise as a portion of the hilled walls of the Hollow. You cannot feel yourself out of doors; plain, sky, and mountains ray beauty which you feel. You bathe in these spirit-beams, turning round and round, as if warming at a camp-fire. Presently you lose consciousness of your own separate existence: you blend with the landscape, and become part and parcel of nature. (John Muir, "Twenty Hill Hollow")

One of the most interesting reads of the last year.

Arkady Kirsanov and Yevgeny Basarov (who embodies the first popular appearance of nihilism in literature) have a memorable relationship in this novel. Turgenev has a compelling style that you can really slip into quickly. I listened to this on audiobook on morning walks throughout the summer, usually spending some time with a few chapters before starting work. One thought that comes to mind at the moment is that I wish I'd read this in my early twenties, just to know how re-reading it now might have felt. Perhaps I'll return to it again in 10 years. I found Bazarov to be fairly insufferable, but empathized with each of the characters - Arkady for his initial idolization of his friend, whose ideas seemed so compelling to him at university, his own personal growth in balancing this discovery with a practical appreciation for tradition, music, and the arts; Bazarov for his cold materialism that is undermined by his own falling in love with Anna Sergeyevna; Nikolay and Pavel Kirsanov for their earnest confusion at the picture of a new generation that leaves them feeling isolated from modern ideas; Anna Sergeyevna for her independence and isolation. Every character seems naive but caught in a search for understanding and being understood, often finding themselves out of time in one way or another.

"Whereas I think: I’m lying here in a haystack... The tiny space I occupy is so infinitesimal in comparison with the rest of space, which I don’t occupy and which has no relation to me. And the period of time in which I’m fated to live is so insignificant beside the eternity in which I haven’t existed and won’t exist... And yet in this atom, this mathematical point, blood is circulating, a brain is working, desiring something... What chaos! What a farce!"

"A man's capable of understanding anything - how the ether vibrates, and what's going on in the sun - but how any other man can blow his nose differently from him, that he's incapable of understanding."

After listening intently to Edwin Barnhart's lecture series on the Ancient Civilizations of North America, I picked up this series, which covers a range of topics on ancient Mesoamerica, focusing primarily on the Olmec, Aztec and Mayan civiliations. It was particularly interesting to learn about the Dresden Codex, one of the four remaining Mayan books, which includes, among many interesting astronomical ideas, the Venus pages, which enumerates dates grouped by the 584-day synodic period of Venus.

I don't usually get into science fiction, but I read this book on a recommendation around the holidays, and I thought it was pretty fun. I love the concept of the enormous cylindrical craft serving as an artificial planet imagined in the book.

I listened to this over the course of several weeks in January and February and was completely fascinated by the lectures. I picked it up while browsing Audible and realizing I had no conception of the history or cultures of ancient North America. While I was familiar with Cahokia, I was intrigued to learn about Poverty Point, North America's first known city, and Poverty Point culture. It was also particularly interesting to learn about the Clovis and Folsom cultures and the ancient fauna of North America. The lectures were accompanied by a 200+ page PDF with maps and photographs of many historic sites and artifacts.

The 1990 audio recording narrated by Rob Inglis is excellent. Inglis's rendition of the songs and poems in the book and voices of the characters brought the recording to life. I enjoyed listening to Tolkien's foreword about the origin of the Lord of the Rings. In the foreword, he mentions his disdain for allegory:

The prime motive was the desire of a tale-teller to try his hand at a really long story that would hold the attention of readers, amuse them, delight them, and at times maybe excite them or deeply move them. ... I cordially dislike allegory in all its manifestations, and always have done so since I grew old and wary enough to detect its presence. I much prefer history, true or feigned, with its varied applicability to the thought and experience of readers. I think that many confuse 'applicability' with 'allegory'; but the one resides in the freedom of the reader, and the other in the purposed domination of the author.'

I enjoy listening to both Jason Fried and DHH talk about business and software development. I appreciate their common-sense, pragmatic approach to running a business. Several key points that stuck with me from this book include the idea to "emulate chefs" by teaching what you know to build a trusting audience, and to always try to "do a job" before hiring for the same position, so that you have some basis of understanding the particular challenges involved. I also appreciate their emphasis on limiting the number of things you try to achieve in order to do them well. This book seemed fairly congruent with Ari Weinzweg's The Power of Belief in Business - a book I enjoyed from his "Lapsed Anarchist's Guide" series, which has a similar unpretentious (yet strongly opinionated) vibe.

If you are trying to decide among a few people to fill a position, hire the best writer. It doesn’t matter if that person is a marketer, salesperson, designer, programmer, or whatever; their writing skills will pay off. That’s because being a good writer is about more than writing. Clear writing is a sign of clear thinking. Great writers know how to communicate. They make things easy to understand. They can put themselves in someone else’s shoes. They know what to omit. And those are qualities you want in any candidate.

This is an autobiographical account of Frankl's experience as a prisoner in Nazi concentration camps. It is a brief, powerful account of the unimaginable suffering of life in WWII concentration camps and what it revealed to the author about human nature. Frankl seeks to understand human experience through the lens of his concept of "Logotherapy," which is based on the premise that the ultimate motivation of any individual is to find a meaning in life. He asserts that life has meaning even in the most unimaginable states of suffering, and that man has the freedom to find it in his actions, life experiences, and his own dispositions, even when the state of the world is not within his control. This book caused me to reflect on writings of the Stoic tradition - particularly Epictetus (the Enchridion).',

I'm currently reading this book based on a recommendation. I really enjoy Schneier's writing style; he covers complex material in the most easy-to-follow manner. He explains each of the protocols detailed in the book at as numbered-list sets of actions between actors, and writes just enough about each topic for the reader to develop a strong high-level understanding. The book covers a range of topics, including many common cryptographic protocols, algorithms, and real world implementations. The breadth and specificity of topics covered is quite wide and varied - everything from common concepts like man in the middle, various one-way hashing algorithms, and public key algorithms, to more esoteric concepts, like zero-knowledge proofs, Ohta-Okamoto identification, or even how Kereberos works - is covered in the text.

There are two kinds of cryptography in this world: cryptography that will stop your kid sister from reading your files, and cryptography that will stop major governments from reading your files. This book is about the latter.

It's interesting to learn from Larson's experience as an engineer and manager. In this book, he covers a great deal about managing software, including sizing engineering teams, managing technical debt, fostering communities of learning, and systems thinking. I'd recommend this book to any software engineer or manager.'

Finally, the one thing that I’ve found at companies with very few interruptions and have observed almost nowhere else: really great, consistently available documentation. It’s probably even harder to bootstrap documentation into a non-documenting company than it is to bootstrap unit tests into a non-testing company, but the best solution to frequent interruptions I’ve seen is a culture of documentation, documentation reading, and a documentation search that actually works.

Most system-implemented systems are designed to support one to two orders magnitude of growth from the current load. Even systems designed for more growth tend to run into limitations within one to two orders of magnitude. If your traffic doubles every six months, then your load increases an order of magnitude every 18 months. (And sometimes new features or products cause load to increase much more quickly.) The cardinality of supported systems increases over time as you add teams, and as "trivial" systems go from unsupported afterthoughts to focal points for entire teams as the systems reach scaling plateaus (things like Apache Kafka, mail delivery, Redis, etc.).

Instead of asking the candidate to explain some architecture on the spur of the moment, give them a warning before the interview that you'll ask them to talk about a given topic for 30 minutes, which is a closer approximation of what they'd be doing on the job. Debugging or extending an existing codebase on a laptop (ideally on their laptop). This is much more akin to the day-to-day work of development than writing an algorithm on the board. A great problem can involve algorithmic components without coming across as a pointless algorithmic question. (One company I spoke with had me implement a full-stack auto-suggest feature for a search inbox, which required implementing a prefix tree, but the interviewer avoided framing it as yet another algo question.)

Have you ever worked at a company where the same two people always got the most important projects? Me too. It's frustrating to watch these opportunities to learn from the sidelines, and reliance on a small group can easily limit a company's throughput as it grows. This is so important that I’ve come to believe that having a wide cohort of coworkers who lead critical projects is one of the most important signifiers of good organizational health.

I decided to pick this up while thinking about works of literature about the prairie and life in the American midwest during the late 19th century. Willa Cather's descriptions of the landscape - its vastness, mystery, and raw beauty - and its profound affect on Jim, an orphan from Virginia, and Antonia, a Bohemian immigrant, are captivating. The real strength of this novel lies in its subtle portrayal of meaningful human relationships. We witness, from Jim's perspective, the formation of a deep bond with his childhood friend Antonia, and its lasting effect on the memory of both of the characters.

Early parts of the book (and in particular, the scene recounting the deadly sleigh ride retold by the Russian immigrant Pavel on his deathbed, wherein he and Peter throw a newlywed couple off of the sleigh he is driving to a pack of wolves stalking the party in order to save themselves) have a fairytale-esque quality.

The last third of the novel has left a strong impression on me; I would recommend this novel. Though there is no way to convey the emotional power of language without greater context, but here are a few excerpts that stuck with me:',

This was the road over which Antonia and I came on that night when we got off the train at Black Hawk and were bedded down in the straw, wondering children, being taken we knew not whither. I had only to close my eyes to hear the rumbling of the wagons in the dark, and to be again overcome by that obliterating strangeness. The feelings of that night were so near that I could reach out and touch them with my hand. I had the sense of coming home to myself, and of having found out what a little circle man's experience is. For Antonia and for me, this had been the road of Destiny; had taken us to those early accidents of fortune which predetermined for us all that we can ever be. Now I understood that the same road was to bring us together again. Whatever we had missed, we possessed together the precious, the incommunicable past.'

In the course of twenty crowded years one parts with many illusions. I did not wish to lose the early ones. Some memories are realities, and are better than anything that can ever happen to one again. She asked me whether I had learned to like big cities. 'I'd always be miserable in a city. I'd die of lonesomeness. I like to be where I know every stack and tree, and where all the ground is friendly. I want to live and die here. Father Kelly says everybody's put into this world for something, and I know what I've got to do. I'm going to see that my little girl has a better chance than ever I had. I'm going to take care of that girl, Jim.' I told her I knew she would. 'Do you know, Antonia, since I've been away, I think of you more often than of anyone else in this part of the world. I'd have liked to have you for a sweetheart, or a wife, or my mother or my sister—anything that a woman can be to a man. The idea of you is a part of my mind; you influence my likes and dislikes, all my tastes, hundreds of times when I don't realize it. You really are a part of me.' She turned her bright, believing eyes to me, and the tears came up in them slowly, 'How can it be like that, when you know so many people, and when I've disappointed you so? Ain't it wonderful, Jim, how much people can mean to each other? I'm so glad we had each other when we were little. I can't wait till my little girl's old enough to tell her about all the things we used to do. You'll always remember me when you think about old times, won't you? And I guess everybody thinks about old times, even the happiest people.' As we walked homeward across the fields, the sun dropped and lay like a great golden globe in the low west. While it hung there, the moon rose in the east, as big as a cart-wheel, pale silver and streaked with rose colour, thin as a bubble or a ghost-moon. For five, perhaps ten minutes, the two luminaries confronted each other across the level land, resting on opposite edges of the world. In that singular light every little tree and shock of wheat, every sunflower stalk and clump of snow-on-the-mountain, drew itself up high and pointed; the very clods and furrows in the fields seemed to stand up sharply. I felt the old pull of the earth, the solemn magic that comes out of those fields at nightfall. I wished I could be a little boy again, and that my way could end there. We reached the edge of the field, where our ways parted. I took her hands and held them against my breast, feeling once more how strong and warm and good they were, those brown hands, and remembering how many kind things they had done for me. I held them now a long while, over my heart. About us it was growing darker and darker, and I had to look hard to see her face, which I meant always to carry with me; the closest, realest face, under all the shadows of women's faces, at the very bottom of my memory. 'I'll come back,' I said earnestly, through the soft, intrusive darkness. 'Perhaps you will'— I felt rather than saw her smile. 'But even if you don't, you're here, like my father. So I won't be lonesome.' As I went back alone over that familiar road, I could almost believe that a boy and girl ran along beside me, as our shadows used to do, laughing and whispering to each other in the grass.'

I heard about this book in late 2016 while watching a YouTube video of Daniel Dennett talking about consciousness. I remembered the title while laying in bed one evening and found the book on Kindle. I purchased a copy and spent the next few hours reading it. The author and the text are wildly interesting. Marais was a South African who lived from 1871 to 1936, working as a lawyer, journalist, poet, naturalist, and newspaper owner. According to his Wikipedia biography, he became addicted to opiates while young, and his wife died as a result of giving birth to their only son. He also had to deal with the plagiarism of his work conducted for this book (by a Nobel Prize winner, no less!). Tragically, he took his own life in 1936. He is recognized as the first person to conduct scientific research of animal behavior in the wild. In this book, Marais examines the behavior of termites and the termite colony in detail. I was struck by the extent of his research. He describes at great length the structure and behavior of the colony - the roles of each type of termite, the sort of hierarchical class structure. Most notably, he may be the first to posit the idea that the termite colony behaves essentially as a complex organism itself - a sort of emergent phenomenon comprised of many smaller, less complex parts, none of which are likely to be aware of the whole. This was a fascinating book and worth picking up.

This was a fantastic introduction to the famous 20th century philosopher. I became interested in Wittgenstein after spending some time reading about Logical Positivism in 2014. I\'d since picked up a copy of this book, as well as the biographies "Wittgenstein" by A.C. Grayling and "Wittgenstein - The Duty of Genius" by Ray Monk. I continue to be intrigued by the picture theory of language as well as the concept of language-game (Sprachspiel), the rule-following paradox, and private language arguments. The philosophies of language and logic continue to be a source of great interest, and I am interested in how they contribute to problem-solving and reasoning about concepts natural language processing and artificial intelligence.

This is a great practical introduction to artificial neural networks. Rashid offers a concise explanation of how they are constructed, and summarizes key points at the end of each section. The second half of the book focuses on implementing the techniques described in the first half for building a neural network from scratch in Python, making use of numpy. I read this through twice, and returned to sections on back propagation several more times. For readers who might be turned off by a lot of math, this seems like a good introduction to the topic. For those who need a quick refresher, the author provides an appendix section dedicated to a few basic concepts from Calculus.