High Quality Content by WIKIPEDIA articles! The Big Four is a work of detective fiction by Agatha Christie and first published in the UK by William Collins & Sons on 27 January, 1927 and in the US by Dodd, Mead and Company later in the same year. It features Hercule Poirot, Arthur Hastings, and Inspector (later, Chief Inspector) Japp. The UK edition retailed at seven shillings and sixpence (7/6) and the US edition at $2.00.