Clarence E. Mulford (1883-1956) was a Brooklyn City Hall clerk when he wrote the first of his popular Bar-20 Western tales in 1905. Beginning in 1935, Hollywood brought Hopalong Cassidy to the screen in sixty-six films. When actor William Boyd sold the Hoppies to television, he touched off the first merchandising bonanza of the video age. This biography of Mulford shows how he was betrayed by his literary creation at the same time that he made a modest fortune. This book, first published in 1991, combines a biography of the writer; a detailed examination of his Hopalong Cassidy and other prose works, and works based on his own characters by other writers such as Louis L'Amour; an overview of the motion picture series; a description of the radio and television shows; an overview of the graphic versions of Hoppy in comic books and newspaper comic strips; a listing of merchandising tie-ins; and a bibliography of published critical, biographical and historical works dealing with Mulford and Cassidy. Because Mulford kept unusually detailed records, this book gives a rare glimpse into the mechanics of writing and marketing popular fiction in the first half of the century as well as a profile of an industrious and fascinating writer and his characters.