I nominate
Pitching in a Pinch by
Christy Mathewson.
This is considered one of the greatest baseball books ever written. Leopold Classic Library issued a new edition three months ago, calling it "a significant literary work."
Because the book was written 100 years ago, it is in the public domain.
Kindle - free
http://www.amazon.com/Pitching-Baseb...dp/B004TPGQP0/
Kobo - free
https://store.kobobooks.com/search?Q...ing+in+a+Pinch
Nook - 99 cents
http://www.barnesandnoble.com/s/Pitching-in-a-Pinch