This is a very unusual Poirot novel in that it has an equal number of suspects and detectives (four in each case). Poirot is invited to dinner by an eccentric acquiantance, Mr Shaitana, who promises to introduce him to four murderers who have got away with their crimes. When Poirot arrives at Mr Shiatana's he finds three other detectives there, enigmatic Superintendant Battle, Colonel Race of the Secret Service, and Mrs Ariadne Oliver, an eccentric writer of detective fiction. The four murderers are elderly widow Mrs Lorrimer, bluff Doctor Roberts, dashing, adventurous Major Despard, and Anne Meredith, a young girl. The two parties, murderers and detectives, settle down to play bridge in separate rooms, and Mr Shiatana sits by the fire in the murderers' room. In the course of the evening he is murdered, but which of the four is responsible? The four detectives set out to solve the crime. As always in Christie's novels there are plenty of humorous touches, one of my favourites is where Superintendant Battle calls for one of the suspects: "I should have kept him to the end" said Mrs Oliver. "in a book, I mean," she added apologetically. "Real life's a bit different" said Battle. "I know" said Mrs Oliver "badly constructed." In the course of the book the detectives find out all the can about the suspects, and learn about the murders they commited earlier (one suspect turns out to be innocent of any murder). There are lots of exciting twists to the plot and you are kept guessing right up until the end. It is apparently possible to find out the identity of the murderer by studying the bridge scores reproduced in the book, if you understand bridge that is. I don't but it doesn't matter, this is an intriguing and clever mystery, definitely one of Mrs Christie's best.