Harry Turtledove 
Departures 

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 streets 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!