Beetz, Kirk H. "John Varley." In Popular World Fiction: 1900-Present. Edited by Walton Beacham and Suzanne Niemeyer. Washington, DC: Beacham Publishing, 1987:1578-1588. Provides an account of Varley's career and critical reception with close readings of The Ophiuchi Hotline, Titan, and "Press Enter Clute, John. "Varley, John (Herbert)."

In The Science Fiction Encyclopedia.

Edited by Peter Nicholls, et al. New York: Dolphin Books, 1979: 628. Brief survey of Varley's early career.

"Varley, John." In Contemporary Authors. New Revision Series. Vol. 25.

Edited by Hal May and Deborah A. Straub, et al. Detroit: Gale Research, 1989: 458-460. Provides a summary of laudatory criticism.

"Varley, John." In Reader's Guide to Twentieth-Century Science Fiction. Edited by Marilyn P. Fletcher. Chicago: American Library Association, 1989.

Offers mostly plot summaries of Varley's fiction, with a brief discussion of his themes and style.