"Natural Hormonal Enhancement" by Rob Faigin. Its the best book I've read on health, fitness, and performance.
"Lights Out: Sleep, Sugar, and Survival". Can't remember the authors but an incredible book on how important sleep and controlling insulin levels is to your total fitness.
"From the Ground UP" by The Dan John, need I say more? btw DJ said in an interview he re-reads "Lights Out" once a year.