From The Art and Popular Culture Encyclopedia
Kilgore Trout is a fictional author created by author Kurt Vonnegut. He was originally created as a fictionalized version of author Theodore Sturgeon (Vonnegut's colleague in the genre of science fiction), although Trout's consistent presence in Vonnegut's works has also led critics to view him as the author's own "alter ego." Trout is also the titular "author" of the novel Venus on the Half-Shell, written pseudonymously by Philip José Farmer.
Trout in other authors' works
At least one actual published work is attributed to a Kilgore Trout: the novel Venus on the Half-Shell, written by Philip José Farmer but published under the name "Kilgore Trout." For some time it was assumed that Vonnegut must have written it; when the truth of its authorship came out, Vonnegut was reported as being "not amused"; in an issue of the semi-prozine Science Fiction Review, published by Richard E. Geis, Geis claimed to have received an angry, obscenity-laden telephone call from Vonnegut about what Farmer had said about the book in Geis' zine.