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.

Curtain: Poirot's Last Case is a work of detective fiction by British writer Agatha Christie, first published in the UK by the Collins Crime Club in September 1975 and in the US by Dodd, Mead and Company later in the same year, selling for $7.95.