When I hear a lecture, If the instructor is the kind I like, then I can easily understand what part of what I'm learning is important and the true crux of the ideas. Like I can pick it up from how the varying their tone , how loudly they speak and how many times they repeat an idea.

However when I read a book, I don't get that same effect. Each idea is stated only once and I have a hard time figuring out what is significant from what is not.

So, when self studying from a book, how do you know which part of a book is significant and important? Or is the described above just a feature of lectures?

Context subjects: Physics and Mathematics


4 Answers 4


how do you know which part of a book is significant and important?

It's all important. Since you mention physics, I'll use the example of Griffiths' E&M book, which goes into quite a bit of detail about waveguides. Many professors (quite reasonably) skip this material, as it is "less significant" than other chapters which discuss general topics like Maxwell's Equations, the Wave Equation, radiation, and relativistic electrodynamics. Yet, waveguides are an entire industry (of which Griffiths only scratches the surface), so I would hesitate to say that the discussion is insignificant or unimportant.

Or is the described above just a feature of lectures?

I think the real feature of lectures is brevity. By turning a long book (or a portion of the book) into 42 bite-sized pieces, it is easier to make sense of things. And once you've had 42 bites, it is easier to read the book and fill in the rest of the gaps. In the absence of lectures, then, you could instead treat each subsection as a "bite", and try to understand it in isolation.

Context subjects: Physics and Mathematics

The key to most physics and math courses is the problem solving. Many introductory students make the mistake of reading the textbook, making beautiful notes, memorizing the examples, etc., but their first time working on a previously-unseen problem is during the exam. In my experience, the ideal balance is almost exactly the opposite -- students should spend ~90% of their time working problems, even if this means they don't read much of the book. For self-study, this means that the availability of a solutions manual is an absolutely essential criterion when choosing a textbook.

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    "I think the real feature of lectures is brevity", that's more of a restriction of lectures isn't it? IMO the feature of lectures is they're interactive, a good lecturer will gauge the reaction of the audience and adapt.
    – Passer By
    Commented Mar 7, 2021 at 23:49
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    I agree with most of the answer (so, +1). Yet, I'm a bit surprised by the sentence "but their first time working on a previously-unseen problem is during the exam", and would be interested to learn where you made this experience. In my experience, almost all math courses (undergraduate and graduate) put a lot of emphasis on problem solving. Commented Mar 8, 2021 at 0:05
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    I am super torn by this answer in a way that I seldom am on SE. Strong agree with "It's all important". Rather disagree with, "students should spend ~90% of their time working problems". Esp. if OP says they do well to find, "the true crux of the ideas". I'm fond of much older textbooks that had a very thin slice more incisive problem sets; I think modern books are bloated and misdirected in that sense. Commented Mar 8, 2021 at 0:21
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    Problem solving is not what physics professors are trying to teach. They should be a collateral skill that results from the students understanding the physics. If a class results in students who can solve problems but don’t understand the physics in them, most professors would consider that a problem. Commented Mar 8, 2021 at 13:22
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    @rpspringuel if solving a problem doesn't require from you understanding physics, then it is a bad problem
    – Mihail
    Commented May 5, 2021 at 2:49

You've accurately described a major advantage of most lectures over most textbooks. A well-written textbook will try to compensate by making good use of highlighting, section separation, introductions/conclusions to sections and other textual features, but this is tricky to do, and to the author often feels like unnecessary padding so that many textbooks end up highly information-dense with little indication of what are considered the key definitions/results/explanations and what plays more of a supporting role.

However, textbooks have a major advantage over lectures which is that they stay put and can be read multiple times, at multiple speeds, and you can easily return to certain parts.

So my recommendations would be:

  • Make sure to pay attention to section introductions and conclusions, since they are likely to signpost the kind of key points/overall structure you are interested in.
  • The first time you read, don't try to commit everything to memory or understand it in any detail. Your aim should be to build up a feeling for the 'geography' of the chapter and how each part fits (roughly) into the wider context. You can then get a sense of what to pay most attention to when you read it a second time.
  • You can supplement this by using other resources simultaneously: for example, you might have the Wikipedia article or a YouTube video open as well. The key points which every presentation mentions are probably important to focus on.

For example, suppose you have a dense analysis textbook. Hopefully the chapter introductions will give a rough roadmap of what the key results in the chapter are, which is a great starting point. Read the chapter fairly briskly, not attempting to follow the proofs, and you will gain a sense for which are the key definitions that get used again and again, and which proofs play a less crucial supporting role. Then you can go through the chapter again in more detail paying attention to those key points.

At the same time, you might have a Wikipedia article open which mentions certain points but doesn't mention others, so that is another indication of what to focus on (although of course notation might differ).


The experimental evidence shows that neither reading a book nor listening to lectures are effective ways for average students to learn physics.

Instead of trying those things, try solving problems. The problems can come from a book or a lecture if you want.

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    This advice does not apply to professional physicists and professors, who are not average students. Commented Mar 7, 2021 at 10:29
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    -1 Link to the "experimental evidence" if that's the entirety of your claim. Commented Mar 8, 2021 at 0:22
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    So: No link and no citation. Commented Mar 8, 2021 at 4:04
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    I very much disagree with this; it doesn't match with any of my experience, either personal or anecdotal. So, absent any sort of corroborating evidence, it is just on-face wrong and not useful. Nor do I see how it even attempts to answer the question that was asked. Commented Mar 8, 2021 at 7:16
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    @CodyGray Your bio says you are a software developer; that is strong evidence you were not a typical student. I will believe peer reviewed, replicated, high sample size experiments and disbelieve your personal experience. Commented Mar 8, 2021 at 8:41

Different people have different ways in which they learn most efficiently. There are four main types of learners:

  • Visual learners who can learn best from diagrams, videos or by making observations in real life.
  • Auditory learners who can learn best from listening to other people.
  • Reading and writing learners who can learn best from reading texts or writing texts themselves.
  • Kinesthetic learners who can learn best from doing things themselves.

It appears that you are more of an auditory learner rather than a reading learner. So when you want to learn about a subject, you might want to try learning from resources like audio-books or podcasts.


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