Simak Clifford. The Goblin Reservation

"First-class entertainment" (The Sunday Times) from a classic SF author. En route to an interplanetary research mission, a scientist is abducted by a strange, shadowy race of aliens and taken to a previously uncharted planet, a storehouse of information that would be invaluable-even to an Earth so advanced that time travel allows goblins, dinosaurs, even Shakespeare to coexist.