This article is from the Kurt Vonnegut FAQ, by George A Cooley firstname.lastname@example.org with numerous contributions by others.
Kilgore Trout is perhaps Vonnegut's fictional alter ego. He is mentioned
in many of KV's books as a little known science fiction writer who is
usually published in pornographic magazines and books with pictures of
"wide open beavers," although his stories have nothing to do with the
accompanying photographs. Frequently, Vonnegut will give a synopsis
of an amusing story written by Trout, as read by one of Vonnegut's main
characters. Trout himself is a main character only in one of Kurt's
novels, "Breakfast of Champions," where Vonnegut actually writes himself
in to his own book, and allows Trout to meet him.