Which Christie novel was published in the U.S. as 'Murder in Retrospect'?

Agatha Christie's Five Little Pigs was published in the United States as Murder in Retrospect.

The Poirot mystery was first issued in America by Dodd, Mead and Company in May 1942 under the alternative title Murder in Retrospect. The British edition followed from the Collins Crime Club in January 1943 under Christie's preferred title, Five Little Pigs. The title reflects the nursery rhyme and Poirot's division of the old case among five central suspects.

Poirot investigates the poisoning of painter Amyas Crale, who died sixteen years earlier. Crale's wife, Caroline, was convicted, but her daughter Carla asks Poirot to reconsider the evidence after receiving Caroline's final letter claiming innocence. The investigation relies heavily on memories and written accounts rather than a fresh crime scene.

The book is sometimes confused with other Christie novels that use alternate American titles, but Murder in Retrospect is specifically the U.S. title for Five Little Pigs. Christie later adapted the story as the play Go Back for Murder, removing Poirot from the stage version.