James Otis was an American author and journalist best known for Toby Tyler; or, Ten Weeks with a Circus. Writing under a shortened form of his name, James Otis Kaler, he produced a large body of children's fiction filled with adventure, historical events, and young people learning to act with courage and resourcefulness.

Born in Winterport, Maine, Kaler began newspaper work while still a boy and later worked as a reporter, editor, and circus publicist. These occupations exposed him to varied settings and supplied practical experience that informed his storytelling. He eventually returned to Maine and served as the first superintendent of schools in South Portland.

Toby Tyler follows a runaway boy into circus life, combining excitement with a recognition of its hardships and complicated loyalties. Kaler's other books include the Boy Spies, Navy Boys, and Minute Boys series, along with stories of colonial settlements and city children. His historical adventures often place young protagonists close to major public events, turning the past into immediate personal experience. His popularity reflects the enduring appeal of briskly told stories in which responsibility develops through action.