Childers' lone masterpiece, "The Riddle of the Sands", considered the first modern spy thriller, is recognisable as the brilliant forerunner of the realism of Graham Greene and John le Carre. Its unique flavour comes from its fine characterization, richly authentic background of inshore sailing and vivid evocation of the late 1890s - an atmosphere of mutual suspicion and intrigue that was soon to lead to war.