The Turnstile is a 1912 political novel by the English author A. E. W. Mason. Cynthia Daventry, the heroine of the story, grows up in Argentina as the adopted daughter of Robert and Jane Daventry, an English couple. Unable to have children themselves, they had adopted Cynthia at the age of three from a foundling hospital where she had been left by her dissolute father, James Glanville, following her mother's death in an earthquake. Cynthia is unaware of her parentage, and is horrified when on her 17th birthday her natural father arrives unannounced to claim her, intending to force her into prostitution in Buenos Aires and live off the proceeds. The Daventrys flee back to England, where they live comfortably although Cynthia never shakes off her deep-rooted fears.