Henry St. John Cooper

Charles Henry St. John Cooper was a prolific English novelist of school and adventure fiction. He wrote thousands of stories for several Amalgamated Press papers, sometimes under the pen name Mabel St. John. He is perhaps best known for creating, in 1908, the character Pollie Green, considered the "most popular, though not the first, in a series of irrepressible schoolgirl heroines". According to his son, he also wrote many "authorless" Sexton Blake stories for the Union Jack. His novel Sunny Ducrow was adapted into a 1926 film, Sunny Side Up.
Actress Gladys Cooper was his half-sister, and musician Henry Russell was his maternal grandfather.