Looking back, history may seem to have unfolded with the inevitability of a movie, but every event represented a crossroads that could have gone any number of ways. Thinking imaginatively and supplying plenty of humor, Hal Johnson depicts 20 mindboggling yet believable scenarios in which the Inca Empire has an air force, Columbus gets driven from the Americas by mounted knights, Hitler maintains a thousand-year Reich, the atomic bomb wasn't dropped on Japan, and Caesar Augustus outlaws bathing.