I liked the book "Babe" by Roger Creamer (or something similar). It was written in the 50's or 60's, but you can still find it. Best Bio of the Bambino. I also liked "Boys of Summer" and some of the writings of Doris Kearns Goodwin (a lousy clintoon apologist, by the way) are among the most entertaining baseball stuff of all time.
I guess I'm getting old. Seems all the good ones are about the 1950's or were written then.