There are numerous stories about Butch Cassidy in Wyoming, many of which were prompted by the 1934 trip to the state by William T. Phillips, alias William T. Wilcox. If Phillips did not actively pass himself off as Cassidy, he did nothing to correct those who thought he was the outlaw. That sparked a debate as to whether Cassidy had returned from South America, having survived a fight with the authorities in Bolivia in 1908. Fortunately, the Works Progress Administration in Wyoming actively set out to gather stories and recollections of Cassidy in an attempt to get to the bottom of the mystery of Cassidy's fate. Those stories became the bedrock of the legend of Butch Cassidy in Wyoming. Many of the stories are untrue, at best misremembrances of events that did not include Cassidy, at worst outright fabrications. But there are some long-overlooked accounts that almost certainly are true and add new detail to the story of Butch Cassidy in Wyoming. Old Men Forget, Butch Cassidy in Wyoming Volume 4, analyses the treasure trove of material gathered by the WPA and sorts the false from the factual. It also tells the story of how and why Cassidy came to be photographed in the Laramie penitentiary, explaining why we now have one of the most iconic photographs in the history of the old West, and the prison photograph of William T. Wilcox, the would-be Cassidy. The story explains why Cassidy did not have his head shaved in his picture, while Wilcox was close-cropped when he was pictured. The tale also busts many of the oft-repeated myths about the Cassidy photograph, including the notion that it shows the injuries he suffered when he was arrested in April 1892. It does not. Old Men Forget narrows down the date on which the photograph was taken to one of two days in May 1895. Finally, Old Men Forget throws new light on the history of William T. Phillips, untangling some of the branches of his complicated family tree and explaining why he used the name Wilcox in Wyoming and Phillips in Michigan and Washington.