[tzs]

Isn't part of that due to math being quite dense? What I mean by dense is that a small amount of mathematics can express things that will take a long time to understand. Because of the density you don't need a lot of pages to contain enough material to occupy a student for a whole semester.

For subjects that are less dense, you need bigger books.

For instance all of the required and recommended books from the courses I took as part of getting a bachelor's degree in math from Caltech take less space on my bookshelf than the required books from just my first semester of law school.

Toss in the second semester of law school and include the non-required books I bought, and that would bring it to more shelf space than all the recommended and required books I bought for all the science and engineering classes I took in four years at Caltech.