Pitching in a Pinch
Pitching in a Pinch (ISBN 0803282125), originally published in 1912, is a book officially written by Christy Mathewson, but more likely ghostwritten. Mathewson had a successful ghostwritten column during the 1911 World Series, and his publisher decided to follow up on its success with a full-length book.
Subtitled Baseball from the Inside, the book uses an insider's perspective on both the game on the field and the character of the players. While some of the stories are probably apocryphal, it remains a good source for people interested in what the game was like during the Deadball Era.