First published, in paperback, in 1967, this is one of two novels Dick wrote in collaboration. Stylistically, it is typical Dick, but it lacks the gravity and conviction of most of his other novels. It's set in the 21st century when the Earth has been conquered by a race of alien, telepathic, wormlike creatures, one of whom, Mekkis, is attracted to the theories of the psychologist Rudolph Balka...