Wave Without A Shore: C.J. Cherryh

Freedom was an isolated planet, off the spaceways track and rarely visited by commercial spacers. The trouble was, tourists and traders claimed the streets were crowded with mysterious sorts in blue robes and members of an alien species. The native born humans claim it isn't so. Such was the belief of Herrin the artist and Waden the autocrat - until a crisis of planetary identity forced a life and depth confrontation between the question of reality and the reality of the question. Cover art by Don Maitz.