What if history had taken a different path, made a detour, and deviated just a little bit from the road it chose? Here, Harry Turtledove explores such "what ifs" in twenty alternate-history stories ranging from ancient times to the far, far-different future. Persia has conquered Greece; Athens is in ruins. Yet even under Persia's rule, the power of the people can never be completely broken. . . A werewolf boy tears through Cologne's medieval stretts in search of sanctuary from the angry mob. But who will shelter a creature so hated and feared? A student from the far-off future sets off on a field trip to study Genghis Khan -- and finds him in the twentieth century? And many more! "He's one of the finest explorers of alternate histories ever." -- Locus