I read a book a year or so ago called the Cheater's Guide to Baseball, by Derek Zumsteg. It was short, and now with video review somewhat dated, but it was a nice discussion of everything from grounds maintenance to signs to spitballs to doping. I enjoyed it, thought Zumsteg's insights into the morality of the game were sound, and learned something about the game as a whole by reading about how players and teams cheated.
Buzz Bissinger wrote a book about Tony Larussa about ten years ago called Three Nights in August. It followed LaRussa for a three-game series against the Cubs. I'm not sure it taught me much about baseball, but its depiction of Larussa's obsession and intensity was unforgettable.
ETA: this was on AndyZ's list as well.