Variants

(1)
  1. Dr. Futurity by Philip K. Dick, in Ace Double D-421, Dr. Futurity by Philip K. Dick / Slavers of Space[/em] by John Brunner (Ace Books, February 1960).
  2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . written by Philip K. Dick