Dumb Witness is a detective fiction novel by British writer Agatha Christie, first published in the UK by the Collins Crime Club on 5 July 1937 and in the US by Dodd, Mead and Company later in the same year under the title of Poirot Loses a Client. The UK edition retailed at seven shillings and sixpence (7/6) and the US edition at $2.00. The book features the Belgian detective Hercule Poirot and is narrated by his friend Arthur Hastings. One novel published after this one features Hastings as narrator, 1975's Curtain: Poirot's Last Case.