Hickory Dickory Dock is a work of detective fiction by Agatha Christie and first published in the UK by the Collins Crime Club on 31 October 1955 and in the US by Dodd, Mead and Company in November of the same year under the title of Hickory Dickory Death. It features her Belgian detective Hercule Poirot. The novel is notable for featuring Poirot's efficient secretary, Miss Felicity Lemon, who had previously appeared only in the Poirot short stories.
This novel is set at a student hostel. Poirot is initially asked to investigate petty thefts and vandalism in the hostel, and easily discovers that most of these acts were committed by resident Celia Austin. Then Celia is murdered.