Robot Series

Robot Series is a collection of novels and short stories that feature positronic robots, written by Isaac Asimov.

There a number of novels, and collections of short stories in the series, and they are almost all part of the same universe as the Empire Series and later the Foundation series.

Most of these novels chronologically appear 20 thousand years before the empire series (prior to the foundation of the Galactic Empire) and the last novel, Robots and Empire, tie the two series together, explaining how the worlds that form the Empire were originally settled.

Also explained is how the Earth became Radioactive (first mentioned in Pebble in the Sky, Asimovs first novel and influenced by the short story Proxima Centauri" by Murray Leinster).