Charles Harold St. John Hamilton (8 August 1876 – 24 December 1961) was an English writer, specialising in writing long-running series of stories for weekly magazines about recurrent casts of characters, his most frequent and famous genre being boys' public school stories, though he also dealt with other genres. He used a variety of pen-names, generally using a different name for each set of characters he wrote about, the most famous being Frank Richards for the Greyfriars School stories (featuring Billy Bunter). Other important pen-names included Martin Clifford (for St Jim's), Owen Conquest (for Rookwood) and Ralph Redway (for The Rio Kid). He also wrote hundreds of stories under his real name such as the Ken King stories for The Modern Boy.