So right now I'm taking two math classes, Multivariate Calc and Abstract Algebra. There is an assigned textbook for Calc, but the professor doesn't use it, and there isn't an assigned textbook for Algebra. I've run into this before in other classes, and I've noticed a trend among professors to have no preference for textbooks, but rather they prefer to teach the material themselves and have the student refer to notes from class in order to do homework and tests. With the internet especially, and also the availability of textbooks in school libraries, I can see why the need for student-owned textbooks has seemed to declined. However, I'm curious as to what others, in math specifically but other sciences as well, think about the need for a student to buy a textbook for a particular subject. Are some subjects more important to have textbooks for than others? Is it detrimental to have no textbook at all? I realize owning certain textbooks may be best in the long run so that you have a reference to refer to in the future, but I'm more specifically interested in learning the material in the first place. Personally, I think I've gotten through two classes without a textbook. I did linear algebra straight from my teacher's notes in class.... and I understood almost nothing, but was able to get an A in the course. The other class was a Techniques of Theoretical Physics class which relied heavily on differential equations and the like. I used a general mathematical encyclopedia to get through that course. I found that referring to my own resource actually helped a lot, because I needed to do a lot of "research" on each problem in order to figure out which equations to use, but in the long run, I was always able to find them, it just took longer. Right now, I'm doing my two classes without textbooks, and its... okay. For Calculus, its fairly straightforward as the examples from class are closely related to our homework. For Algebra, its a bit more difficult and I find myself online A LOT trying to understand concepts we brush over in class, but require a firm grasp of in order to do the homework. So... My overall opinion is mixed. But I'm fairly young career-wise, so perhaps those with more experience in their studies have a more formed opinion? Textbooks, necessary or no?