The Timesweepers
The Devil You Don't
The Time Thieves - (original title= "The Star-Sent Knaves")
The Other Sky - (a.k.a. "The Further Sky")
Mind Out of Time

Original appearances from 1963 to 1971 - from Analog, Worlds of Tomorrow, Amazing, The Farthest Reaches, and Alchemy and Academe. "The Timesweepers" formed the basis for the novel Dinosaur Beach.