American Football - How the Game Evolved
by James Herget
James Herget's history is concise, but it does a good job of describing how American football gradually evolved and who some of the major players were that affected those changes.
It covers the game from it's early roots at the collegiate level and traces how it evolved from Association Football (soccer) to the rugby game and beyond. It provides an important timeline for rules changes along the way, and gives some good background on why those changes occurred.
It's a quick read that serves as a starting point for fans interested in how the game developed and evolved. Perhaps, one of the most important items in the book is the bibliography at the end that lists a number of other books that have been written through the years about the sport's development.