In 1961, Lawrence Block was living in New York and earning a living writing Midcentury Erotica and crime fiction. He'd just sold his first book under his own name, Grifter's Game, to Gold Medal Books. (They insisted on calling it Mona, but the original title's been restored by Hard Case Crime.) His agent got him an assignment to write a tie-in paperback novel for Belmont Books, linked to the TV series Markham, starring Ray Milland. The book turned out well, and the young writer's agent felt it was too good to be a Belmont tie-in. Knox Burger agreed, and Block changed the name of the hero from Roy Markham to Ed London, and Gold Medal published the book as Death Pulls a Doublecross. (Another unfortunate title; you'll find the book in the Classic Crime Library with the author's original title, Coward's Kiss.) But that left Block owing Belmont a book. You Could Call It Murder is what he wrote for them, and it turned out fairly nicely as well, but his agent sent it to Belmont all the same, where they published it as Markham: The Case of the Pornographic Photos. (By the time it came out--surprise surprise--the TV series was canceled.)