
The Art of Computer Programming—NOT for the reason you expect. The series is simultaneously fantastic and terrible. Being able to articulate why the series just plain sucks even though it’s also really good at the same time. 90% of the time, if there’s something I want to look up in TAOCP, I can just go for a walk, realize whatever I’m trying to do is unnecessary work, and come back and work on actual important stuff I care about. The other 10% of the time, I get better answers from digging through the citations on Wikipedia.
Exercises for the Feynman Lectures on Physics—Yes, the exercise book, not the lecture book. I know it’s not CS or math. The way that the problems build on each other is spellbinding. For example, there’s an early problem where you calculate the mean free path of air, but you’re not given a formula for it—you’re just given a series of problems which provoke you to think about the subject in a way that you can figure out a formula for it yourself.