I am a second-year undergraduate student and in autumn I'll be starting my third year and after that there is the final fourth. I've come accross someone's lecture notes on eBay. The same uni. It's several years old so some stuff will have changed. It's not the ones we would receive from the lecturers, it's own work albeit based on lectures contents.

Nothing relevant to the assignments is there, only the theory. I intend to prepare during the summer to jump ahead because I want to pursue more advanced topics so it's not strictly out of laziness. I want to learn faster and I question the level of teaching, they don't care about initiative and ambition and I feel like they're holding me back.

Is there anything wrong with that?

  • 41
    why do you think there might be anything wrong with that?
    – sleepy
    Commented Jun 7, 2021 at 18:31
  • 23
    There exist universities that sell such lecture notes officially. Commented Jun 7, 2021 at 22:25
  • 17
    We were sharing or giving out the notes for free. Perhaps is the buying that does not sound very good :)
    – Alchimista
    Commented Jun 8, 2021 at 9:01
  • This seems to be a version of another Q: how much should I prepare for a class in advance? Should I read the book over the summer? etc... . To me it's a waste of time. Read stuff where you took the prereq but didn't understand a few things, or things where there's no class. Commented Jun 8, 2021 at 13:36
  • 2
    Many textbooks are merely repackaged sets of lecture notes, with exercises. Commented Jun 8, 2021 at 20:31

5 Answers 5


I don't see anything wrong. If it were answers to exam questions, or even homework, then I'd be concerned. But the notes give you an alternate explanation of many topics and that is very useful (and proper). Books do the same, of course.

It is a fact that not every explanation of a complex topic is equally informative to a student. Having an alternative way of looking at topics can give you insight that you might not get from the lecture alone. It also gives you a way to prepare for an actual lecture beforehand, so that you are more likely to pick up the important points.

The earlier notes can also be a source of questions for the instructor, or for yourself.

But don't use it as an excuse not to attend the lectures, or pay attention. Additionally, since the act of making notes (read: actively and efficiently summarising the important points of a lecture), is, for most people, a very good way to learn, it would most likely be a mistake to buy the notes as a substitute for making your own.

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    If it were answers to exam questions or even homework, then I'd be concerned Why would you? Homework or exam questions are ultimately just exercises. They should not be secret, and the lecturer should not rely on such a secret (because people who passed the exam last year can share the details)
    – WoJ
    Commented Jun 9, 2021 at 15:33
  • Also worth noting that someone else's notes may or may not be helpful to you. What is deemed noteworthy and the way notes are recorded can vary greatly from student to student. If you purchase someone else's notes, be mindful that while they may have been perfectly adequate for the original author, your own mileage may vary. Commented Jun 9, 2021 at 17:18
  • @WoJ Sometimes lecturers reuse exam questions, so buying the exam questions from previous years can be a form of cheating - you should ask the lecturer for permission first, to verify that it's okay, before you study previous years' exam questions.
    – nick012000
    Commented Jun 10, 2021 at 11:32
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    @nick012000 I have to disagree. Homework and exam questions are public knowledge - from the moment one shard them with 100 or 500 people one cannot expect that they will be secret. There may be copyright concerns (I do not know much about that) but not cheating. We have (in France) books about the exact questions of past exams (you can also download them free) and they won't repeat.
    – WoJ
    Commented Jun 10, 2021 at 13:11
  • Here in Germany it is very common to buy exam solutions for a small fee (it is even officially encouraged). If your professor/lecturer is so lazy to require to keep solutions secret, they are pretty bad imo and not doing anyone a favor (since solutions will always leak no matter what). Also (at least in math/CS) it is often encouraged to solve homework together. And for lecture notes, many professors give out their notes (sometimes several hundred pages long) for free (digitally)
    – adjan
    Commented Jun 10, 2021 at 13:31

There's nothing ethically wrong with using resources outside of class for the purpose of teaching yourself the material. If anything, going beyond what you are given in the course to educate yourself is wonderful and indeed something that is expected at the graduate student level.

Having said that I would just add a few words of advice.

  • You might want to check that you are getting the best resource for the money you are spending. If you don't want to spend money, there are lecture notes for many undergraduate (and graduate) level courses online for free that you can use. If you do want to spend money, you could also consider buying a book (or you could borrow a book from the library if you don't want to spend money). Are you sure there is material in the lecture notes you can't get another way?
  • Of course another set of lecture notes not used by the professor will have some differences in emphasis, notation, order of material, and so on. Ultimately you will have to turn in assignments and take exams from your professor, so you may need to translate what you learn from other sources into your professor's notation / way of thinking.
  • It is a good thing to be ambitious and to supplement your own education. But, generally it's not a good idea to assume your professors are not doing their best to provide a good education; even if you don't see the point in what they are teaching you at the time, as you advance you may see that foundations were being laid for later courses.
  • 7
    The cost was quite honestly symbolic. I read textbooks, books and original publications too. There are mistakes in those notes but that's not a problem because I can spot them as I develop understanding. I never take anyone's word for it anyway, I choose what to believe. Commented Jun 7, 2021 at 18:38
  • @Peter In that case, sounds great!
    – Andrew
    Commented Jun 7, 2021 at 18:40
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    @Peter I realize I misread and thought "lecture notes" meant "notes written by a professor" as opposed to "notes taken by a student." I still don't think there's anything wrong (assuming there aren't solutions to homeworks you aren't supposed to have or something), but I would put a bit more weight on the "make sure you are getting the best resource" bullet point. Make sure the person is good, the notes are readable, etc.
    – Andrew
    Commented Jun 7, 2021 at 20:47

To reiterate points made in other answers and comments: no, in terms of learning things (!!!), it is absolutely fine to make use of other peoples' prior work. It would be laughable if we all had to reinvent the wheel, etc.

Yet, yes, there are some forms of academic stuff wherein there are "rules" prohibiting looking at all the stuff out in the world. The most ridiculous type is "it's not ok to use an idea not covered yet in the course".

The latter concept only makes sense if "education" is an exercise in conformity to authority, rather than ... education. It's ridiculous.

Nevertheless, I hear gossip that some people do ridiculous things. Incredible... in a bad way.

EDIT: yes, certainly, as mentioned in comments (and as many people know), there is substantial reason to understand "what implies what", and often a sort of annihilating over-kill is far less enlightening than a more-restricted-means explanation.

In fact, questions which may be extremely awkward from a too-elementary viewpoint that become transparent from a more sophisticated viewpoint are things that I myself like to emphasize to my students in graduate courses. Not everything does yield to a more sophisticated viewpoint, of course. But quite a few of the introduction-to-advanced-math questions are indeed hardly tractable from an elementary viewpoint (and this is visible historically, motivating a great deal of modern math!), but/and become mundane from our contemporary viewpoint (which was motivated by wanting to mundane-ize such questions, hm!).

  • 1
    Regarding "it's not ok to use an idea not covered yet in the course", I think there's a difference between learning about an idea not covered yet in a course and using it for solving assignment problems. The former should of course be completely allowed, but it might be reasonable to put temporary restrictions on the latter if it helps in mastering a specific idea currently being covered. (But this is somewhat beside the point, and +1 for the answer).
    – GoodDeeds
    Commented Jun 7, 2021 at 22:07
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    Here's a reasonable example of "not ok to use an idea not covered in the course" (in math): if a homework assignment is to prove a special case of Theorem X, with the idea that this homework will serve as ground work for a later lecture that will actually prove Theorem X, then turning in an answer like "this problem is true because it is a special case of Theorem X" is not really doing anyone any good. The key thing is to understand the ideas and to understand your prof's expectations. Anyway I +1-ed this answer, I think the idea is right.
    – Andrew
    Commented Jun 7, 2021 at 22:24
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    You can always use any method you want but if it hasn't been covedred then you must prove it. If it's an exam and the proof would be too long then it's not usable. But if a specific method is stipulated than using that partucular idea is part of the assignment and you must use it. Commented Jun 8, 2021 at 7:41

I agree with the answers already provided in that there is nothing "wrong" with purchasing the lecture notes, but I would add one question to you in return:

"Is it optimal?"

Your intentions to use it as a supplement rather than a replacement are admirable but you should know that some fields move quite quickly. If it were lecture notes on, say, web technology or some software API, then I would say "Don't waste your money". That's an extreme example because web technology and some software packages move pretty quick and you often want to start your learning with the most up-to-date technology. Even "history" gets updated as new finds are uncovered, although the pace might be slower than technology.

If some of the courses have changed lecturer, or been updated, you might find that ploughing through 2-year-old notes is irrelevant, confusing and a waste of effort. But you should be able to tell quite quickly as long as you're using it as a supplement rather than a replacement.


If it is a verbatim copy of the blackboard, it might be a copyright violation.

  • Interesting point - the lecturer is writing notes up/slides that contain wording for the physically-present students to learn and remember, with the intention of them writing it down. Noone would call that copyright violation, so is it the Selling ?
    – Criggie
    Commented Jun 9, 2021 at 2:09
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    @Criggie IANAL, whether Selling or free, it involves making additional copies. If OP is in Eritrea, Turkmenistan or San Marino it might be legal, but is it "wrong". Commented Jun 9, 2021 at 3:34
  • @KeithMcClary: When are the "additional" copies made? The students make notes in the lecture, which is a copy, sure, but they have permission for that (and so not a violation). If they then sell that copy they made in the lecture, no extra copies are made.
    – psmears
    Commented Jun 9, 2021 at 10:18
  • @psmears The student received the original presentation of the lecture, not the students' notes. The student's notes are a derived work of which the lecturer and the student are co-authors. The two co-authors must agree to any redistribution of the notes. The exact legal theory is likely different from country to country, but I think the gist would be the same pretty much everywhere. Commented Jun 9, 2021 at 11:10
  • @psmears (cont.) In France, the student has permission to make and modify copies (the student's notes) for the student's private use, but not to redistribute these copies (unless they were redistributing the lecture presentation itself, which is materially impossible). Selling the notes without the approval of the lecturer, who is a co-author, is a copyright violation. In the US, this would fall under “fair use”: taking notes during a lecture is fair use, but selling the notes isn't. Commented Jun 9, 2021 at 11:10

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