Courtney Ryley Cooper (October 31, 1886 – September 29, 1940) was an American circus performer, publicist and writer. During his career he published over 30 books, many focusing on crime; J. Edgar Hoover considered him at one time "the best informed man on crime in the U. S." He was also an expert on circuses, and was the chief publicist for Ringling Brothers, Barnum & Bailey Circus at the time of his death.