Cicely Disappears is a 1927 mystery novel by the British writer Anthony Cox, written under the pen name of A. Monmouth Platts. Berkley used a variety of pseudonyms during his career, in this case based on two properties he was associated with in Watford.

It was originally serialised in The Daily Mirror during 1926 under the title The Wintringham Mystery. The newspaper held a competition with prizes for those who could give the best answers about the mystery. One of the winners was Colonel Archie Christie, husband of the celebrated crime writer Agatha.

Cox's first novel, The Layton Court Mystery, was published anonymously in 1925. It introduced Roger Sheringham, the amateur detective who features in many of the author's novels including the classic Poisoned Chocolates Case. In 1930, Berkeley founded the Detection Club in London along with Agatha Christie, Freeman Wills Crofts and other established mystery writers.

His 1932 novel (as "Francis Iles"), Before the Fact was adapted into the 1941 classic film Suspicion, directed by Alfred Hitchcock, starring Cary Grant and Joan Fontaine. Trial and Error was turned into the unusual 1941 film Flight from Destiny starring Thomas Mitchell.