Three Act Tragedy is a detective novel by Agatha Christie, first published in the US by Dodd, Mead and Company in 1934 under the title Murder in Three Acts, and in the UK by the Collins Crime Club in January 1935 under Christie's original title. The book features Hercule Poirot, supported by his friend Mr Satterthwaite, and is the one book in which Satterthwaite collaborates with Poirot.
