Thrilling Wonder Stories and its sister magazine Startling Stories played an important early role in his career. His controversial early novel The Lovers first appeared in Startling in August 1952 (see corner illustration) before being expanded for a book version in 1961. His novelet "Mother," in the April 1953 issue of Thrilling Wonder, explored Freudian themes as a stranded explorer becomes, in essence, both fetus and lover to an alien creature. A sequel, "Daughter," appeared in the Winter 1954 issue.
Perhaps his most popular work was the Riverworld cycle of stories and novels about a planet-wide river valley populated by every person who has ever lived and died. The Sci-Fi channel produced a TV movie/series pilot based on the cycle in 2001, and aired it in 2003.
His use of existing literary characters and worlds included fictional biographies of Tarzan and Doc Savage (in which he connects them genealogically to numerous other fictional characters), a novel in which Sherlock Holmes and Tarzan team up, a science fiction sequel to Moby Dick, a novel filling in the blanks of Around the World in Eighty Days, and a book about the adventures of Dorothy's barnstormer son in Oz. He also wrote authorized Tarzan and Doc Savage novels.
Under the name of Kilgore Trout, the brilliant but unrespected science fiction author who appears in a number of Kurt Vonnegut, Jr's, novels, he wrote Venus on the Half-Shell in 1975. He wrote numerous other "fictional author" stories, including, in a second remove from reality, one as by a character whom Farmer had created as Kilgore Trout in Venus.
A longtime Midwesterner, Farmer was born in Terre Haute, Indiana, and died in Peoria, Illinois, where he had spent most of his life.