A CHOICE OF GODS

Simak, who puts solid ground beneath the feet, or claws, or simply slime of his creatures, sets his handful of pleasant people -- an elderly pair of civilized landowners, noble Indians, and a wandering ""hunter"" -- along with some culturally developing robots on an abandoned but reviving Earth after the rest of humanity is mysteriously off to the stars. The dreaded return of the Earth-exploiters is avoided when robot mutation catches a bloodless outer galactic ""Principle"" in logical error. Talky but typically ingenious.