The Machine

A Hot Team, A Legendary Season, and a Heart-Stopping World Series:
The Story of the 1975 Cincinnati Reds
Joe Posnanski - 2010 HarperCollins Publishers

Most Entertaining Baseball Books I've read thus far:
1. Ball Four
2. The Bullpen Gospels
3. The Machine

It's hard to encapsulate the enjoyment of this book in a few short words but suffice it say that it's one of those you'll stay up into the early hours of the morning racing to finish.  I did.