Middle Limit Book

[Moyer]

In my opinion, SSH, Weighing the Odds, & How Good is Your Limit Holdem are by far the best and are books you can completely build your game off of if you need to.

Honorable mentions go to HPFAP, Inside the Poker Mind, and Theory of Poker. These should also be mandatory reads for anyone getting serious about limit poker.

Real Poker II, Internet Texas Hold'em, Ace on the River, all of the Poker Essays, Middle Limit Hold'em, IYP, and SS2 are all worth reading if you like to read and if you're careful each of these may help you at least a little bit.