Speedy is an American boy who twice visited the Land of Oz.
Speedy is an orphan. When he was two years old, his parents died while exploring the South Pacific; their ship was wrecked in a hurricane. The boy lives with his Uncle Billy, a talented inventor, in a large rambling house in Garden City, Long Island, New York. Speedy's devotion to his uncle prevents him from staying in Oz when his adventures are done.
Uncle Billy's full name is William J. Harmstead; Speedy was named William after him. The boy acquired his nickname from his prowess at baseball and track and field. It is unknown whether the elder William is Speedy's paternal or maternal uncle: Speedy's family name might be Harmstead...or something else.
Like Ruth Plumly Thompson's other main child protagonist, Peter Brown, Speedy lacks a normal nuclear family. The guardians of both boys (Speedy's uncle and Peter's grandfather) are eccentrics who tolerate and support the boys' trips to Oz.
Thompson utilized these two boy heroes, Speedy and Peter, in five of the eight Oz novels she wrote between 1927 and 1934.