The Citadel is a novel by A. J. Cronin, first published in 1937, which was groundbreaking in its treatment of the contentious theme of medical ethics. It has been credited with laying the foundation in Great Britain for the introduction of the NHS a decade later. In the United States, it won the National Book Award for 1937 novels, voted by members of the American Booksellers Association.Ballots were submitted by 319 stores; there had been about 600 ABA members one year earlier.