I graduated from college with the distinct impression that there are two types of college professors.

The real ones: Those that don’t mind you buying/using 3 year old used textbooks, and

The institutionalized ones: Those that will fail you if you haven’t purchased the latest version of the same textbook.

I could say that if I was studying quantam mechanics or fiber-optic research I might need the latest and greatest. But for subjects that are directly derived from Principia Mathematica and the like, 1999 vs. 2002 versions don’t matter, do they?!

Principia Mathematica college professors