"Polly of the Circus" is a novel by Margaret Mayo that tells the story of Polly, a young orphan girl who is raised in a traveling circus. Polly lives an unconventional and joyful life with her adopted circus family, where everyone from the trapeze artists to the clowns becomes her surrogate family. However, her life takes a drastic turn when a local minister, John Douglas, convinces her to leave the circus and live a "normal" life with him. The story is about Polly's love for her circus life, her struggle to fit into conventional society, and her complicated relationship with John.