It is a textbook. Typically, students don't read text books cover to cover (and often read very little or none). Instead, they perhaps read some of the few sections that are listed in the syllabus and follow the lectures and do the homework because that's usually what's on the test.

Outside academia those things are not an option and part of what makes a good book is that it can be read and reread over a long period of time and still be relevant.

One of my favorite essays:

http://norvig.com/21-days.html