Ask HN: How do you synthesize books that you read? | Hacker News Reader

Ask HN: How do you synthesize books that you read?

49 pointsjnac60 comments

When you read nonfiction (i.e. Designing Data Intensive Applications, Thinking in Systems) how do you 'lock in' your understanding and apply it to your daily life?

Have tried note-taking, book reports, services like Readwise personally.

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When I used to be an overintellectualizing, overacademizing nerd, I would use complex and regimented notetaking and review systems. The whole gamut from trendy notetaking wiki-type apps to flashcard spaced-repetition apps like anki.

These things made me feel like I was learning. Flashcards and notetaking itself were fun games. I felt like I'd stumbled onto this hyper-optimized efficient way to learn whatever I wanted.

That feeling was misplaced.

I threw away all that garbage and just started diving into things after reading/observing the bare minimum to get the wheels rolling. Read a little, act a lot. The acting is the most important part. You want to learn some thing? Just do that thing, repeatedly.

It's inefficient, failure-laden, and it's the best way to truly learn something.

This applies to abstract things too, like math and language. Don't bother making flashcards for theorems, syntax, or word definitions. You gotta do the work. For math, just do a million exercises. For language, read, write, listen, speak. You can flashcard word definitions and atomic little rules all day, and you'll feel like you're making progress, that's how Duolingo reels in so many people. It's an easy way to feel like you're accomplishing, but it's a facade. Gotta just do the work.

> "Read a little, act a lot. The acting is the most important part. You want to learn some thing? Just do that thing"

Took me a long time to learn this but also came to the same conclusion.

I agree with basically everything you are saying, except I think a sprinkle of rote memorization can go a long way in some domains. Whenever I read a math book, memorizing definitions and some key theorems helps me apply them in problems. With programming, however, I tend to do zero rote memorization.

Math actually takes it to an extreme. I did not expect that and spent a few months reading math textbooks thinking I'm studying it. Maybe doing some basic exercises and moving further right after.

> It's inefficient, failure-laden, and it's the best way to truly learn something.

I think there's value in documenting the errors/failures one ran into, and reflecting on them in hindsight. That is what actually shows one's learning process.

Beautifully put. It's been a while since I've read a book and immediately thought, "Wow, this is so inspiring, my life will be completely changed if I can apply this!" I think this is more a function of my age rather than the quality of the books I've read recently.

Just about everything I read—fiction or nonfiction—will impact me in some small way, whether it's a useful new phrase, a novel concept, something explained in a new way, or a new perspective. I'm fine with just absorbing what I can and allowing it to enrich my (hopefully) continuing process of gradual self-improvement.

For languages, I think it depends on the language and the learner. Flashcards helped me learn all ~2,000 of the Jōyō kanji in about 18 months.

"One learns from books and example only that certain things can be done. Actual learning requires that you do those things." (Frank Herbert, Children of Dune)

This applies to abstract things too, like math and language. Don't bother making flashcards for theorems, syntax, or word definitions. You gotta do the work.

I sort of disagree with this, at least with the naive interpretation. That is, if one is saying that "the work" is mutually exclusive with memorizing "theorems, syntax, word definitions <and etc.>" then I definitely disagree. I would posit that "The work" includes (but is not limited to) doing that memorization. So I'd rephrase the original statement as "Don't ONLY make flashcards for theorems, syntax, or word definitions. You gotta do the other work too" or something close to that.

IOW, I think memorization using Flashcards (whether using Anki or not) is a valid part of the process of learning and synthesizing things. At least in my experience, it's a part that adds value for me. But I would agree that just doing that is not sufficient in and of itself.

Generally agree.

There is a case for writing down the stuff you learned though (into your notebook, app, zettelkasten, whatever). When I try to note down a concept I learned, I feel like sort of explaining it to myself. And often, I will quickly discover holes in my understanding. A good note-taking software can also point out connections to other stuff (mostly in the form of other notes) I maybe wouldn't have made. Maybe others don't need that, but I am bad at making connections.

This is me too. Learning by doing means making mistakes in real life rather than things remaining in the realm of intellectual exercise where everything is neat and tidy.

Some people have a linear happy path to learning — they seem to be able to acquire all the right knowledge and avoid mistakes.

But I learn from doing the wrong things — the resulting cognitive dissonance burns the lesson into my head. This is an expensive way to learn because you have to make a lot of mistakes and bear the resulting shame. But over time I learned to avoid fatal mistakes and make the merely stupid ones.

I’ve always been inspired by a quote by Goro Shimura about his colleague Yutaka Taniyama (both of the Taniyama Shimura Conjecture fame, which led to the proof of Fermat’s last theorem):

“He was not a very careful person as a mathematician. He made a lot of mistakes. But he made mistakes in a good direction. I tried to imitate him. But I've realized that it's very difficult to make good mistakes.”

"Pitting the learning of basic knowledge against the development of creative thinking is a false choice."

- make it stick: Brown, Roediger, McDaniel

I listen to a lot of non-fiction audiobooks. Over time, I've realized it's pretty much pointless to try to "lock-in" knowledge. There's simply too much information and generally a lot of noise, relative to the real-world problems I'm solving.

I now read books with a few intentions:

* Don't read for facts. Read for patterns and mindsets.

* Spend enough time in the book to absorb a mindset from it. I don't need all 8.5 hours of Eric Ries's "The Lean Startup", but spending 8.5 hours in the book helps me stew on topics.

* Focus on outcomes and problems/solutions. It's far more valuable to know how and where to find 100 solutions than it is to memorize 10 solutions.

For something deeply technical, like Designing Data Intensive Applications, I'm not reading it to understand the specifics of the solution. I'm reading it to understand the broad strokes of problems varies solutions solve. If I need the details, I'll come re-read a few relevant sections for the specific problem I'm solving.

For less technical books, like business books, it's really about taking one or two topics away that resonate deeply with me. I don't necessarily need to remember why they resonate deeply with me. I just need to be able to remember the principles when I'm in a relevant situations.

This is the way. Let the book flow through you and change how you think. Embed that stuff deep in your neural network, if you will.

You can always look up facts later if you need them. What matters is getting the vibes and an intuitive feel for the material.

Directional understanding is what I am for. Details, that’s what search is for.

I also like to read in audio, then get a paperback copy if I think later I’ll need to reference details.

Synthesizing the core thesis into a blog/article in my own words helps a lot too. But really good books ooze through all future thoughts and writing anyway.

edit: explaining the ideas to a friend also does wonders. “Hey I read this book about …” works great

> I also like to read in audio

I envy you. I just can't "read" in audio. I understand and retain almost nothing. Same with lectures, etc. Actually reading appears to be an essential component for me.

> I just can't "read" in audio

I used to think so too! My listening comprehension is just sad.

But it works great for the "let it flow through you" approach. It feels like I retain nothing and have no idea what I've read. But if I just try to trust my brain and repeat back or explain the content, without feeling like I know it, the words that come out of my mouth are correct.

The key may be that I do this listening while running. Keep the body busy so I don't distract myself and let the mind wander with audio playing in like a guided meditation style.

My background theory is around schematization. Our knowledge is a complex web of inter-related concepts. Some factual, some abstract.

For audiobooks/read books, I look for 2 or 3 key "aha moments" that stick with me. For Thinking Fast it was "two ways of thinking", "loss aversion". From there other related concepts are just below the surface.

For Thinking in Systems it's "stocks + outflows + inflow", and "all systems reach an equilibrium".

As you read more, you get lots of different ideas cross pollinate, and from there you gain your own insights.

As others have said, pondering or applying the ideas in real life is really important.

I say that I learn best by reading (which is true), but an essential component of that is that I find ways to actually use what I'm learning -- because I really learn best by doing.

If the book is about making data-intensive applications, for instance, I'll write such an application as I work through the book, using the concepts that I'm reading about.

I'll also not worry about memorizing every bit of knowledge in the book and instead strive to remember what information is in the book so that when I need to know something specific, I know where to look.

I've found note-taking to be worthless to me, but I know that many people find it valuable.

This is my answer. How do you know you've learned something? If you're learning how to build something, you know you've learned it when you can build it.

Fiction is a little tougher, but I've found conversations with my wife help me here. If I can make her as interested in the story as I am, then I must be retaining enough of the important points to say I'm absorbing enough of what I'm reading.

>because I really learn best by doing

It's not just you - everyone learns best by doing

I have a method that works really well.

I only read books on kindle, and i use kindle highlights. After I finish a book, I usually wait about 1 month or so, then I download the kindle highlights and turn them in to Anki flash cards and review them every day.

The type of cards i make are

1. vocab i didnt know 2. interesting paragraphs 3. other examples using cloze

SMS works, and this method definitely works, but it's a lot of work. One really good thing that comes out of this is even if I cant recall exactly what I wanted, I always can remember the book it came from and the kindle highlights give me the page number to go read it again.

I guess this isn't applicable for technical books, i.e. you don't read them on a kindle?

I do not read them on kindle, but it works with technical concepts. Check this out

http://augmentingcognition.com/ltm.html

Anki for the win! There's nothing like it if you want to retain large amounts of detailed knowledge.

My approach is similar! However, my cards are more made for spaced reading than for spaced repetition studying. As such, each card just corresponds to a highlight.

(Also replace Kindle with Google play books)

does your method work well ?

I don't really understand the question. When I read a nonfiction book, if it brings a new perspective that changes my understanding, then it changes my understanding as I read it, I don't do (or need to do) anything else. And if it has something that I want to apply to my daily/work life, then I apply it to my daily/work life when I read it (not as some special process after reading the whole book), handling it the exact same way as if I got "that something to apply" from a chat at lunch or a HN post or a shower thought.

Ya same here these days if I like a book and it impacts me -- it will change me! If not, then not.

Depends on the type of book.

coding book -> jypter notebooks.

physics/ math book -> a notebook with the feynman method.

History, general reading -> rewriting your understanding in a narrative word doc.

Always have a 'Why' when reading. Play with the problems and use the concepts towards some 'end' not in the book.

edit: "How to read a book" is a good book.

I think it's a great advice. I'd also add that reading a book from cover to cover without a clear application of the knowledge can be wasteful in terms of time and retention, and might lead to feeling motivated to finish the book as opposed to understanding it.

Learning on the fly for me personally is a more suitable approach: determine what I'm lacking and build a dependency graph of things I need to understand before achieving it. The n conquer the individual topics.

That's literally what I do though... I keep journals of what I read. I work on problems if the book comes with any problem sets. I summarize key topics in my own words.

If the book doesn't have problem sets, per se, I come up with ways of testing myself that I understood the material usually through a small side project or by revisiting something I did before and trying to rework it using the new knowledge I'm trying to gain.

I also do this for fiction. I keep journals of all the books I've read, what I was thinking about at the time, my impressions while reading it, interesting passages that stood out to me, etc. I re-read books and I write new journal entries for the second (or third, etc) reading: context and history often change how I think about, react to, or enjoy a story.

Thinking to me starts with writing.

It varies, but one big thing I do goes as follows:

1. Read the book, taking notes on a wiki page dedicated to that specific book (I self-host a Mediawiki install for stuff like this). In this first pass, I tend to take really detailed notes, at times practically transcribing large portions of the text.

2. Re-read these notes a couple of times. Add hyperlinks to related material, read related material, etc. I may also edit the notes to reflect better understanding, or just to fix typos and suchlike.

3. Start a new page called "<Book Name> Synthesis". In here I rewrite my notes, but very specifically not direct transcription. I write what I think about the topic, based on my reading(s) above.

4. Re-read the notes from (3) above every now and then. Possibly editing for clarification or whatever as I go.

5. At some point I may do a synthesis page that synthesizes my thoughts from multiple related books on a similar theme or topic.

So yeah, that's a lot of work and it doesn't scale to being done for every book I read, not even close. But it's what I do when I really want to focus in on something specific and really do an intensive deep-dive.

The other thing I will sometimes do is make an Anki deck from the book I'm reading, and then review those periodically.

Outside of that: if it's a programming book, I usually code up the examples / exercises, and then depending on what it is I may extend myself to push and do things beyond the provided examples / exercises (like a book on a new programming language I'm just learning, for example). For a book on something related to electronics, I may well assemble and test circuits on a breadboard, take measurements with the oscilloscope / spectrum analyzer / etc... And so on. What tangible artifacts come out of reading a book really depends on the book. I might even be reading a book on "Foraging for Wild Edible Plants" and the tangible outcome might be tonight's dinner. shrug

I have success retaining information by explaining it to another human being. This can lead to me rereading sections and keeps me engaged with the content.

This is consistent with what I have read from "Your Memory : How It Works and How to Improve It" by K. Higbee.

This is the best way I've found for clarifying and cementing my understanding of a nonfiction book. Two great opportunities for this conversation can be discussing the book you're reading with your partner, and recommending a book to a friend.

It's said that "the best way to learn something is to teach it to someone else", and I think there's a huge hunk of truth there!

I don't use your method to help digest books, but I use it heavily when I'm working through a particularly difficult programming problem. And I've found that the less the person I'm explaining to knows about the subject, the more effective the process is. I think it's because it forces me to break the problem down to the bare fundamentals so they can understand what I'm saying.

Bit of a shameless plug but I've been thinking about this for a while and I recently built a free/open-source tool called Emdash [1] to tackle the problem. I’m a heavy ebook highlighter, but I found if I didn’t have a compelling way to review those highlights they fell out of my understanding.

My tool uses on-device semantic embedding which allows you to peruse your collection and see related passages from other books which I find really helps in comprehension when you view a related idea in the words of another author. You can also search for semantic concepts directly to see nearby ideas from various authors, which is nice for when you’re in a mood for exploring a particular space via raw concepts.

The demo mode also previews a passage rephrasing feature, which can give you a simplified or metaphorical explanation, which I’ve found really valuable in grokking dense excerpts. This part is powered by LLMs (off-device) but will be opt-in later. I’m trying to gauge interest for it, so there’s a form to sign up for a waitlist if you’d like.

Would love to hear if anyone else uses this tool and what they’d like to see in it. Source code is available too [2].

[1] https://emdash.ai

[2] https://github.com/dmotz/emdash

This is a beautiful app - my problem with tools like this is I don't use a Kindle so ingesting highlights is painful, but I'll plan on giving this a shot nevertheless.

I will probably not sound very sophisticated, but I would say I just dive in.

E.g. If I want to learn about some historical period/character, I will just read books over books about it until my brain just naturally adsorb it.

If I want to understand CS/nath topics, I will just try to implement what I want to understand until I get it.

Is it akin to banging my head against the wall until I break the wall? Yes. Is it the most efficient way? Probably not. Does it work in the end? Yeah.

I only read nonfiction (since I was 8 because a teacher told me I couldn’t check out any more nonfiction books from the library).

Just read the entire book in as little time as possible. And then try to use the information as soon as you can.

The reason is that isolated facts are easy to forget. A book contains a great many facts all related to each other. So if you read the book quickly the greater likelihood that you’ll associate more of these facts together. If you can use the information, even better, since it’ll reinforce what you learned. And/or read a more advanced book on the same topic immediately after.

People often take a really long time to read nonfiction, causing them to forget a lot of details, making it difficult to build this relational model of the information. Build up your tolerance for learning. It’s entirely possible to read for the entire day from waking up to going to sleep.

And no, this does not involve taking notes or breaks (unless you finish the book.. then do whatever you want but I find sleep after to be helpful for remembering).

As a systems-minded reader-person:

I like to ask an LLM for 3-5 good ways to know that one really understands the content in question.

Then I ask for examples of each of those, used in a specific setting (code for an app or script I need / project I'm working on, for example).

I also like to pre-read the book based on podcast interviews, YouTube summaries, and so on.

If the book is written from first principles, I will probably find it easier to work through it backwards, as the back of the book is typically where the most functional interfaces to the "world I already know" are demonstrated in such books.

To me this is also a common sign of someone who's a natural systems thinker (since you mentioned the topic): First principles are the wrong end of the learning process.

A natural systems thinker may even hear the phrase "first principles" and immediately start to feel boredom, impatience, and time escaping their grasp. :-)

A systems thinker needs access to working interfaces for systems components first and foremost, not internal components and logic.

This is due to the broad nature of systems work, the interconnectedness of its scope, and so on. Internal logic and single-component foundations focus will effectively block efficiency here.

If it really is more about internal logic of a system's individual component, then this is not systems thinking. Generally here is where you find departure points from systems thinking into more academic-style criticism or analysis. Arguments are definitional in nature and less about work products, economy, or outcomes.

(I also keep a running log and own-structure system if the topic is important to me)

Just some thoughts, good luck.

On what level of topics do you query LLMs to help you learn? As you become a domain expert, the usefulness of LLMs diminishes, I imagine?

Regarding the learning of learning from first principles vs from 'working interfaces', could this be said as 'learning top to bottom' (high-level ideas first) vs 'bottom to top' (low-level first, e.g. understanding axioms of real numbers before understanding algebra)?

Good q's...

I find that domain expertise is really a funny mirage in a lot of ways.

What I want in reading a book is less often book-domain expertise and more often "convert book's contents to my thinking style and existing systems fit." Then I will typically use that result in the domains in which I'm already an expert...that's what I generally find that I want.

For this reason the LLM is helpful in abstraction duties. It doesn't by itself need to be as much of a domain expert, as much as it needs to give me e.g. more fluid interface-mindset access.

On the other hand, if it is lacking even basic quality of internal schema, sure? It's just that this hasn't happened to me yet; maybe that's surprising but it's more likely that this happens based on my own specific questions and theories than with the contents of published books.

So many of the books are functionally general in nature but still foreign in their nomenclature, etc. and I find that this is a good leverage point for an LLM.

> could this be said as

It usually is said that way, in my experience. I personally find it more helpful to talk about interfaces vs. internals. But others may be more used to talking about top-down.

For example with the interfaces metaphor, you get to have more than one "top" which maps very well to systems focus & benefits IMO. The leverage here is very useful in some teaching and learning cases.

ChatGPT (gpt-4.0) is crazy omniscient.

It doesn't diminish, the knowledge is like a fractal. You can zoom out, in, etc.

I created a prompt that asks me a set of questions on a topic. It then scores my understanding, gives me deeper insight into the topics, broadens my understanding with some extra information, and then provides a mind-map of related topics, and a mind-map of adjacent topics.

To bootstrap an area of understanding, I ask it for a mind-map of a topic. Like a fractal, you can choose a line item and go deeper.

Prompt 1: Give me a small mind map on the amygdala

Based on that, prompt 2: give me a mind map on the role of the basolateral nuclei of the amygdala in the creation of phobias

I’m surprised that nobody mentioned Readwise in the comments.

It’s such a good service if you read a lot of digital books and gives you 10 highlights from the bokks you’ve read everyday!

Check it out: https://readwise.io/i/rishikesh2

Readwise reader is my go-to for articles; just hard to ingest from physical books.

I recently discovered I have aphantasia. I lack the ability to visualize anything with my mind's eye, it's just blank. As I've delved into what aphantasia is and how it affects my brain processes in general it became very apparent to me that what I learn, how I learn, and my ability to retain that learning are deeply tied to my inability to visualize and the coping mechanisms I've developed to compensate.

Visualization, just like every trait, is a spectrum. I would recommend anyone analyzing their learning methods to take the Vividness of Visual Imagery Questionnaire (available at https://aphantasia.com/vviq) and see where you fall on the spectrum. I am about as far on the aphantasia side as you can get but my wife is the opposite and is considered a hyper-visualizer. The condition was named from the visual aspects but it can effect all senses. I can't hear music or imagine what voices sound like. I can't do impressions of people, I can't draw, I can't play guitar, etc. Some people with aphantasia can though so it's not a hard and fast rule. But making those realizations about myself has lifted a burden I didn't know was there. I can sell my guitar and stop being frustrated about why lessons aren't working. I can stop trying to draw pictures that look nothing like my intentions. I can stop wondering why I have no memory of where my wife left her keys. Most importantly, I could identify my coping mechanisms and focus on improving them.

Exploring the differences between how we think and learn has been a huge help to me personally, professionally and with my relationships. Not many specifics for OP's question but I just want to share awareness of Aphantasia and help others start their own journey of self-reflection and improvement.

EDIT: I thought of one specific example of how I learn that may help. There is something about the physical aspect of doing that solidifies something into my memory. The cool part is the physical act of writing something down counts for me. I can write something down and then throw away the paper and I will usually remember it just fine. It's the physical motions that trigger my brain to form the memories.

Wow, I've always wondered if I was the only one or how to even describe it in one word. Thanks for this. I dont have much creativity because I can't imagine in my mind, I have to put it down on paper. I can't draw from my mind, can't put a tune together. But I can copy patterns well.

When I was a kid, I was taught to 'narrate' the books I read - fiction, nonfiction, whatever - just 'tell it back in your own words' at a reasonable level of detail. That helped a ton with retaining most of what I read, as it trained me early on to remember it clearly. Don't really have to bother with explicit retention methods.

That, plus generally reading because there's specific information that I need to get out of the materials. Working on some project, need to know how to do something, find & read resources that help me do it.

Externalization FTW!

You don't know something until you try to spit it out in your own words in a way that make sense.

As an example, you think you know what a bike looks like. You do, right? Draw it without cheating. 95% of people I've asked - can't. After drawing it have a look at https://www.gianlucagimini.it/portfolio-item/velocipedia/

I like to highlight in the books. These highlights are words that make me think or resonate with me.

After each chapter, I'll go into a Notion Doc and type out these highlights. Then following the highlights I'll write my thoughts or summarize the highlights in own words.

Sometimes these thoughts turn into full-blown essays. Sometimes these thoughts are nothing.

But I still get the reps in.

After the book is done, I publish some highlights and the thoughts to my personal website.

I think one needs to be clear about what type of content one is learning. Is it rote memorization like anatomy? Or is it more conceptual like system design?

It seems to me that you want to apply memorization techniques, or even high school paper writing techniques, to material highly conceptual in nature...

I don't think that's appropriate.

There are a few things you need to do:

- reread/rewatch/relisten (not necessarily the whole thing, just parts (and at varying intervals))

- talk about and/or explain it to and with others

- read negative takes on what you just read/saw/heard (not just positive ones)

- actually do whatever it is you think you've learned

Simple and judicious note-taking as I read the book for the first time, by pen & paper; then I usually leave those notes tucked into the front of the book, and for a couple years, I revisit and review those notes every few months. At some point I might re-read the book.

I find that I retain the most information when I build myself a “story” of it. A kind of narrative makes it easy to relate from one piece of knowledge to another, and also interject new tidbits as you find them. Things like obsidian lend themselves really nicely

If I find a non-fiction book interesting, I will often find similar books to read for related perspectives or do focused web searches on sections that I don’t understand well or find particularly interesting/useful.

Explain it to somebody else.

Similar idea here. I take notes as if I'm explaining it to someone else or expecting someone else (or myself in a few years) to read it.

When I took my Instructor Methodology class to become a Firefighting Instructor, I recall the gentleman who ran the class exposing me to the quote (which I've come to embrace wholeheartedly) that goes "You don't really understand something until you've taught it to somebody else."

"Understanding How We Learn" by two cognitive scientists.

https://www.learningscientists.org/books

Anki helps.

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