[1] The Gaean Reach includes all worlds colonized by humans, among which trade and travel flow freely for the most part.
Some of these worlds are advanced and cosmopolitan, such as Alphanor; others, like Thamber, are inhabited by shipwrecked and forgotten people who have reverted to feudalism.
"[2] The period of the Gaean Reach spans several centuries, if not millennia, at an indeterminate but very distant time in the future.
The Reach is mentioned in the three Alastor books, the Cadwal Chronicles, Ports of Call and Lurulu.
Standalone works set in the Gaean Reach include Emphyrio, Night Lamp, Maske: Thaery and The Gray Prince.