A man without memory, stranded on an icy asteroid. His only chance for survival is locked within a band of mining robots who are dutifully searching the surface for a mysterious object known as the Key to Perihelion. His name is Derec. His journey will take him to a city different from any he has ever known. A fantastic metropolis beyond his Robot City.

An amnesiac man and a woman stranded in a city of robots, Derec and Katherine are the only logical suspects in a case of murder, and their identities and the name of the murderer are two of the mysteries to be solved. Reprint.

A man without a memory, trapped in a city of robots gone wild. At his side, a mysterious woman who claims to know his identity but refuses to tell him. Together, they must find an insane cyborg stalking the streets of Robot City, a time bomb indistinguishable from the ordinary robots.

Derec, a man without a memory, and Ariel, an enigmatic woman, move through Robot City searching for a dangerous cyborg who has gone insane and trying to root out the cause of a growing epidemic of "roboticide." Reprint.

A man without memory, in a city of robots gone wild. At his side, a mysterious woman whose own identity he has reconstructed, and whose memories of him may be true or false. The young man calls himself Derec. In the shattering climax to his quest he discovers the shocking secret of his true identity. Tormented by a nightmarish disease, Derec must face the genius Dr. Avery, and compel him to reveal the truth!

Derec, an amnesia victim, learns the secret of his true identity and must face Dr. Avery, the deranged scientist who controls Robot City

Ace Books, 1989. Mass market paperback original; first in a series of six novels written by various authors and loosely connected to Isaac Asimov's "Robot" series.

Ariel follows her lover, Derec, to a planet of robots, where Derec is summoned to solve the mystery of the robots and aliens before a robot war erupts

The machinery of Robot City has gone mysteriously awry, and Derek, who has only recently returned, is determined to locate and eliminate the source of this distressing reprogramming

Derec has restored the original Robot City, but now three subversive robots of his mother's creation are urging a robot revolution that threatens to destroy his father's city