One of the best selling authors at the moment is Timothy Ferriss. He is the author of The 4-Hour Workweek and The 4-Hour Body.

He is a little trailer from the 4-hour body book with my favorite band Sevendust:

Tim Ferriss has a vast knowledge of training and is well known in the Crossfit community. He is a RKC Kettlebell level 2 instructor under Pavel Tsatsouline. Tim has put the last 10 or so years of his own experience in training into this book and there are some pretty amazing things in it. I highly recommend both his books.