Earth Made of Glass
In a sequel toA Million Open Doors, John Barnes writes another novel in the universe of the Thousand Cultures. Humanity dwells in colonies (some natural and some artificial) spread over hundreds of planets that lost touch with each other for over a thousand years.  Due to the invention of thespringer, an instantaneous teleportation device, the worlds are communicating again.  But after centuries of isolation, reunification results in intense cultural and economic stress.Giraut and Margaret, characters from the earlier book, are now a husband and wife diplomatic team for the Council of Humanity.  They also do clandestine work for the Office of Special Projects, an undercover organization that deals with serious problems that result when local governments prove intractable. Their next assignment: promote peace and cooperation on Briand, a hellish planet whose physical hostility is matched only by the hatred its two cultures show to each other.Tamil Mandalam was founded by classical Tamils, and Kintulum was founded by classical Mayans. Tamils believe themselves to be perfect and believe that once the springer does open Briand to humanity, they will show the rest of the universe how to live. The Mayans, when they communicate at all, apparently feel the same way. The magnificence of each culture's accomplishments in art and literature is overshadowed by citizens' bigotry.A difficult assignment indeed; as if high gravity, high temperatures and ethnic attacks weren't enough, Giraut and Margaret's mission grows even more troublesome because of their marital problems, Margaret's depression, and the bureaucratic thick-headedness of Briand's Ambassador.--Bonnie Bouman