American writer noted for his stories of innovation in sword-and-sorcery, contemporary horror, and satiric science fiction.

Leiber, the son of stage and film actors, studied at the University of Chicago (Ph.B., 1932) and the Episcopalian General Theological Seminary (1932–33) and performed on stage and in films before his first published story, “Two Sought Adventure,” appeared in 1939. The story introduced the characters Grey Mouser and Fahfrd, who were featured in a series of swashbuckling adventure fantasies collected in The Three of Swords (1989) and Swords' Masters (1990). Leiber was also a pioneer of horror stories with modern urban settings, beginning with “Smoke Ghost” (1941) and continuing in his early novels such as Gather, Darkness! (1950), in which a religious dictatorship is conquered by science disguised as witchcraft, and Conjure Wife (1953).

In the early 1950s, the height of McCarthyism, the politically liberal Leiber was noted for his savagely satiric works about a chaotic, crumbling America, including the short story “Coming Attraction” (1950) and the novel The Green Millennium (1953). The satire is less harsh in his later fiction, which includes The Silver Eggheads (1961), a farce on the publishing industry, and A Specter Is Haunting Texas (1969), which mocks war, racism, and hypocrisy. Leiber's later short stories, such as “Gonna Roll the Bones” (1967), “Ill Met in Lankhmar” (1970), and “Belsen Express” (1975), are among his most admired works.