[MarkG509]

"Hacker's Delight" by Henry J. (Hank) Warren. Despite the unfortunate title[0], it teaches (with code) numerous tricks, algorithms, ideas, that really improve performance and function of programs.

[0] not "hackers" as in those who try to crack into systems, but rather as in those who enjoy writing professional, clever, and efficient code.

[thrownaway2424]

Get the 2nd edition, of course. It's three times as long.

I don't know if I've ever really learned anything from Hacker's Delight, though. It's more of a cookbook. If I learned anything it's that a lot of dead CPU architectures were hard to program.