Human Test — E.M. Foner

Sequel to Turing Test - Read that book first. Imagine a world populated by human refugees removed from Earth. Now imagine they're producing handicrafts for the galactic luxury market. Mark Ai and his expanded team are deep undercover on Reservation, a world the Ferrymen populated with humans transported from Earth between the Bronze Age and early Iron Age. The mission is to discover if the Ferrymen are violating the Sky God rules of the League of Sentient Aliens Regulating Space, but it soon becomes clear that everything is not what it seems, and the observers are themselves under observation.