Gridiron football or American football or just plain football is the most popular sport in the United States in the 21st century. Although attempts have been made to develop the sport outside North America, it is still predominantly a North American sport with similar games (but significant rules differences) played in the United States and Canada. The Historical Dictionary of Football covers the history of American football through a chronology, an introductory essay, appendixes, and an extensive bibliography. The dictionary section has over 600 cross-referenced entries on both amateur (collegiate) and professional players, coaches, teams and executives from all eras. This book is an excellent access point for students, researchers, and anyone wanting to know more about the sport of football.