Archibald Joseph Cronin (19 July 1896 – 6 January 1981), known as A. J. Cronin, was a Scottish physician and novelist.
His best-known novel is The Citadel (1937), about a Scottish doctor who serves in a Welsh mining village before achieving success in London, where he becomes disillusioned about the venality and incompetence of some doctors. Cronin knew both areas, as a medical inspector of mines and as a doctor in Harley Street. The book exposed unfairness and malpractice in British medicine and helped to inspire the National Health Service.
The Stars Look Down, set in the North East of England, is another of his best-selling novels inspired by his work among miners. Both novels have been filmed, as have Hatter's Castle, The Keys of the Kingdom and The Green Years. His 1935 novella Country Doctor inspired a long-running BBC radio and TV series, Dr. Finlay's Casebook (1962–1971), set in the 1920s. There was a follow-up series in 1993–1996.
