The League That Didn't Exist: A History of the All-American Football Conference, 1946-1949

The All-American Football Conference was the only challenger to the NFL (except for the American Football League of the 1960s) to survive more than two seasons in competition with the established league. It ultimately failed to achieve its goal of a peaceful coexistence with the NFL and folded in 1949. Its Cleveland Browns and San Francisco 49ers, which were absorbed by the NFL in 1950, are still in business.