Pebble in the Sky

One moment Joseph Schwartz is a happily retired tailor in Chicago, 1949. The next he's a helpless stranger on Earth during the heyday of the first Galactic Empire. Earth, as he soon learns, is a backwater, just a pebble in the sky, despised by all the other 200 million planets of the Empire because its people dare to claim it's the original home of man. And Earth is poor, with great areas of radioactivity...