Dumb Witness

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. It is the last book to feature the character of Hastings until the final Poirot novel, 1975's Curtain: Poirot's Last Case, which he also narrates.

Reviews of this novel at publication in 1937 were generally positive, though several pointed out what they considered to be plot weaknesses. The author does "this sort of thing so superlatively well", while The Times in London questioned one of the actions by the murderer: "who would use hammer and nails and varnish in the middle of the night near an open bedroom door?" In the New York Times, this novel was not considered "Mrs Christie's best, but she has produced a much-better-than-average thriller nevertheless", which is a view shared by "Torquemada" (Edward Powys Mathers), who called this "the least of all the Poirot books" and then concluded "Still, better a bad Christie than a good average." By contrast, Mary Dell considered this novel to be "Mrs Christie at her best". The Scotsman felt the author deserved "full marks" for this novel. A review in 1990 found this novel to be not very interesting, with obvious clues.