William T. Phillips
William T. Phillips (1863 – 1937) was a Spokane, Washington author, best remembered for The Bandit Invincible, a biography of the outlaw Butch Cassidy. A copy of the book is held at The American Heritage Center at the University of Wyoming. Phillips claimed to have known Cassidy since childhood, and states in his book that Butch Cassidy's real name was not Robert Parker. Some have speculated that Phillips was Butch Cassidy but there is no evidence to support the claim.
In 2012, Larry Pointer stated that the original, unabridged manuscript of The Bandit Invincible had been brought to him for authentication by a collector in Utah. In it he found previously unknown references to an associate of Butch Cassidy's by the name of William T. Wilcox, who was described as having been in Wyoming Territorial Prison with Butch Cassidy. Given the name's similarity with "William T. Phillips," he searched for a prison mugshot of Wilcox. Upon receiving it and observing the similarities between the two men, he revised his previous theory and concluded that Phillips was in fact Wilcox, instead of Butch Cassidy.
- Pointer, Larry (1988). In Search of Butch Cassidy. Oklahoma: University of Oklahoma Press. ISBN 0-8061-2143-2. (William T. Phillips is the subject of this book.)
- What Ever Happened to Butch Cassidy? Unsolved Mysteries, NBC, 13 February 1991 (included a discussion about William T. Phillips)