The 66 Hopalong Cassidy pictures were filmed by independent producers who released the films through the studios. The first "Hoppies", as the films were known, were distributed by Paramount Pictures to favorable returns, and United Artists was the distributor after Paramount. They were noted for fast action and outdoor photography (usually by Russell Harlan). Harry Sherman wanted to make more ambitious movies and tried to cancel the Cassidy series, but popular demand forced Sherman back into production, this time for United Artists. Sherman gave up the series in 1944, but William Boyd wanted to keep it going. To do this, he gambled his future on Hopalong Cassidy, mortgaging most of what he owned to buy the character rights from Mulford and the backlog of movies from Sherman.