What is the purpose of textbooks?

Question

I as a student have done various courses at my university and for each of these courses a textbook was prescribed. On the other hand, the instructor provided his notes as well. The textbook was huge (approximately 500 pages) whereas the lecture notes were only 100 pages and really short and clean. During my studies, I rarely used the textbook but relied on the notes and I think that I just did fine. I am not the only student who rarely uses prescribed textbook but other students also think the same in my classes. The students that I talked to prefer notes mainly because

• textbooks are expensive so not everyone can afford buying 5 textbooks each academic session (5 subjects per session) which makes it 10 textbooks per year and the average price for each textbook is $150;
• textbooks are huge (about 500 pages) so students prefer to use notes which is clean, short, and summarized;
• It is true that during an academic session, a student studies for a particular subject, but he may forget some of the material so he needs to study it again few days before the exam. Studying a 500 pages textbook few days before the exams is practically impossible given the stress and pressure that students face when they get near the exam.

The only benefit of the textbooks that I can tell is that if you find a particular concept unclear, you can look at the textbook for clarification but most students really do not do this. If they struggle with a particular concept, they go to the office hours of the instructor and ask for clarification. The textbooks also have many exercises so if any student needs to do more exercises, they can uses the prescribed textbook but I have not seen any student who does this.

What is the purpose of a prescribed textbook in a course taught by instructor and why do instructors emphasize reading it?

Answer 1

The question is based on several false premises and this also leads to an answer:

[…] students prefer to use notes which is[sic!] clean, short, and summarized

That's not true for many students. In fact, there are students who dislike summarized text and like textbook style.

It is true that during an academic session, a student studies for a particular subject, but he may forget some of the material so he needs to study it again few days before the exam. Studying a 500 pages textbook few days before the exams is practically impossible […]

Textbooks have a table of contents and often an index, so it is not at all impossible to brush up on a certain topic using a 500 pages textbook last minute (given that you know the context and some buzzwords).

[…] you can look at the textbook for clarification but most students really do not do this.

Many students do this, really.

If they struggle with a particular concept, they go to the office hours of the instructor and ask for clarification.

Some come to office hours, some don't. For my courses, only very little students come to office hours and most study by other means - presumably some read a textbook.

The textbooks also have many exercises so if any student needs to do more exercises, they can uses the prescribed textbook but I have not seen any student who does this.

Look harder. There are these students who do additional exercises.

Last point: Textbooks are used by professors to create their courses. There are great textbooks for introductory courses and professors do not want to reinvent the wheel (well, a worse wheel, actually). If they rely on textbooks for their preparation, why not tell the students which books they used?

I don't know if there are courses where you really have to purchase a textbook - you may just decide to not buy it and may be fine. I prefer to announce textbooks that are available online through subscriptions of my university and in the library as a paper copy (with at least one "permanent/reference copy" that can not be borrowed) so that the students can use the book for free.

Answer 2

Sorry for the long answer, but the title of the question scares me, and brings visions of a world where few (nobody?) value textbooks anymore (the horror!). So I knew I had to jump in. This is my (a student's) perspective on why textbooks are important in a course.

textbooks are expensive [...]

As a computer science undergrad from India, I do sometimes feel a pinch in my pocket while purchasing particularly expensive textbooks. This rarely happens, however, since I view the money spent on textbooks as an investment for my education – much like the tuition fee for my university. Moreover, many authors (and sometimes universities) generously provide free PDF copies of textbooks online for personal use; for example Computer Vision, Deep Learning.

The textbook was huge (approximately 500 pages) whereas the lecture notes were only 100 pages and really short and clean.

There are a couple of very simple reasons for this. Firstly, A (good) textbook is written in a manner in which new material is introduced gently, giving background information and building the idea from the ground up which makes the concept seem simple and intuitive. For instance, in our course on compilers, we use the legendary Dragon Book, which when read judiciously builds up complex ideas from scratch in a manner that makes them seem trivial, when they are obviously not. (To appreciate this – if you have done computer programming before, and find it hard, consider how hard it must be to write a program that can correctly decode a general computer program to make the computer understand what to do).

Secondly, I don't know which course you study, but if it is something that can have a strong mathematical background (such as CS), then I doubt if your instructor's notes will do justice to the material in terms of elucidating the underlying proofs, analyses, etc. In a subject like CS where these aspects are crucial parts of the material, omitting them for the sake of simplicity doesn't seem like a good idea. The notes are an aid to learning, they are not a replacement for the textbook.

During my studies, I rarely used the textbook but relied on the notes and I think that I just did fine.

That is very common, unfortunately. Although I always read the textbooks for all classes I take (I love textbooks :D), I am often not among the top scorers in a course. My observation is that this is because most of the top-scoring students in a course do not study the material, they study for tests. They restrict themselves to instructor's notes and test questions from previous test papers to prepare themselves for tackling the test well. They do not spend time in building the ideas from basics, which is what textbooks are for.

textbooks are huge (about 500 pages) so students prefer to use notes which is clean, short, and summarized

As Dirk mentioned, that's not really true.

It is true that during an academic session, a student studies for a particular subject, but he may forget some of the material so he needs to study it again few days before the exam. Studying a 500 pages textbook few days before the exams is practically impossible [...]

As Dirk mentioned, it is not impossible to revise smartly from textbooks using the index, etc. But my personal opinion on this is that textbooks are sometimes not very efficient for revisions / studying for exams. For these, your own notes (made during lectures or while reading the textbook) or your instructor's notes can be a useful aid (not a replacement).

The only benefit of the textbooks that I can tell is that if you find a particular concept unclear, you can look at the textbook for clarification [...]

That is not the only benefit of textbooks! As I mentioned earlier, (good) textbooks provide context to the material, they are responsible for building ideas, not simply providing information. In my opinion, if you really want to understand and appreciate a subject, then this deep, contextual learning by building new ideas over old ones is an important journey – and an enjoyable and fulfilling one too!

If they struggle with a particular concept, they go to the office hours of the instructor and ask for clarification

Perhaps this is not a problem with you, but I (and many of my peers) have often suffered due to the lack of a qualified instructor for a subject. During such times, textbooks have been the guiding light for many students like us. It was during times like these when I realised the value of textbooks.

Finally, a good textbook is usually written by a person well experienced in the field, for the sole purpose of explaining the material to the reader. If you do have the opportunity to meet such an expert in person, who has the time, patience, and skill to frame his thoughts in a simple and coherent manner, then do go talk to him – but still save your textbooks because you can read them again and again over a period of years ;).

Answer 3

A personal experience from a math student:

Concepts, proofs and derivations in the lecture (notes) are written one way. Sometimes / Often this way is not understandable to you, so you look for a different approach, a different wording, a different start for a concept in order to understand it.

The examples in the lecture notes usually only cover the most common cases, but in the exercise sheets other cases are asked to be solved.

Now, these things can be found in textbooks. But nowadays many of these things can also be found online, i.e. Wikipedia or various forums. For the textbooks, as Dirk mentioned, some are available for free, online, if your university has a contract with the publisher, and there's always the library.

To answer your question: The purpose of a textbook is to provide you with a different perspective.

Answer 4

As an instructor, I'm often led to cringe by the price of textbooks. I often tell students pretty upfront that I understand if they opt not to purchase the textbook, but that they are doing so at their own risk. While I try to explain things clearly myself, I also tell students that the textbook has a slightly different - and often complementary - angle on most things (and different examples, and a useful glossary at the back, and interesting tangents for those interested). The students who both come to class and keep up with the reading are: a) getting more exposure to the material (spaced repetition reportedly being a very good thing for learning, though I'm far from an expert), and b) having things explained to them again in different terms, so more of it is likely to stick in the first place. Since most of my midterms and exams reward conceptual understanding more than memorization, it is to my students' advantage to work through my notes and the textbook while studying (as well as asking me questions, etc.).

Answer 5

textbooks are huge (about 500 pages) so students prefer to use notes which is clean, short, and summarized

There are several dangers to this - first, the clean, short, summarized notes don't have all the details, whereas a textbook might. Indeed, the notes may be missing essential details because they are in the textbook itself.

Additionally, and I've experienced this twice in my career, there is a benefit to having information from two different sources. If you don't understand someone's presentation of material during a lecture, it's possible you won't understand that same person's presentation in the notes. Having a textbook, written (often) in a different voice, may be exceedingly helpful.

It is true that during an academic session, a student studies for a particular subject, but he may forget some of the material so he needs to study it again few days before the exam. Studying a 500 pages textbook few days before the exams is practically impossible given the stress and pressure that students face when they get near the exam.

To be blunt, failing to leave time to study for an exam is a failure of the student, not the textbook. Additionally, said hypothetical student should only need to read some sections of the textbook - though which sections those are may vary by student.

The only benefit of the textbooks that I can tell is that if you find a particular concept unclear, you can look at the textbook for clarification but most students really do not do this.

[Citation Needed]

Also, I don't plan things for what "most students do". I plan for what a student should be able to do to fully engage with the course and material.

If they struggle with a particular concept, they go to the office hours of the instructor and ask for clarification.

And it's entirely possible the instructor will say "Chapter 3 covers this really well...". Or, as noted, that there may genuinely be a disconnect between how the instructor explains something and how the student understands it.

Answer 6

Another seasoned student here, coming from Germany.

The only benefit of the textbooks that I can tell is that if you find a particular concept unclear, you can look at the textbook for clarification but most students really do not do this. Well, I don't usually care about how other students do their work. In fact, compared to the average students, I'm quite quick in understanding things and often do so during the lecture, not by studying after. However, of course I too came across concepts I couldn't understand using my notes, and certain textbooks helped me overcoming my shortcomings.

As others mentioned already, you should also take into account who has written the book. Different authors have different styles. I could name (German) authors which I completely understand and some which have a terrible style of writing, for my taste.

The textbooks also have many exercises so if any student needs to do more exercises, they can uses the prescribed textbook but I have not seen any student who does this. Again, bad for them. Of course there are exercises which may be not easy to solve and not being statements that are much of interest, but by trying to solve them alone you can improve your understanding of the topic because you look up definitions etc.

The other answers have covered pretty anything else, but I would like to answer the title question directly (ignoring the "in lectures" part).

1. Textbooks are not for students only. When you specialize in a mathematical topic and you notice that for your research, some other topic may be of interest as well, before you speak to any colleague you will first provide yourself with the basics of the new topic from a textbook, to get the general idea.
2. Mathematics is a lot of fun and wonder. Once someone is intrigued with the beauty of mathematics, why not look up some math that is not covered in your courses? This way I learned about knot theory and topological vector spaces. Most students here will sadly never know about this stuff unless it is covered in a seminar they stumble into. (In fact, just today someone I know told me he is now in a course of chaos theory and then I asked what happens in this course :-) )
3. There are not only beginner's text books but also such that cover certain topics that were only discussed in papers previously. And believe me, collecting a bunch of relevant papers can be time consuming. So I was really happy I came across something called "Selected topics in Graph Theory".