Poirot Investigates is a short story collection written by Agatha Christie and first published in the UK by The Bodley Head in March 1924. In the eleven stories, famed eccentric detective Hercule Poirot solves a variety of mysteries involving greed, jealousy, and revenge. The American version of this book, published by Dodd, Mead and Company in 1925, featured a further three stories. The UK first edition featured an illustration of Poirot on the dust jacket by W. Smithson Broadhead, reprinted from the 21 March 1923 issue of The Sketch magazine. Poirot receives a visit from Miss Mary Marvell, the famous American film star on her visit to London. She has received three letters, handed to her by a Chinese man, which warn her to return her fabulous diamond jewel, the "Western Star", to where it came from – the left eye of an idol – before the next full moon. Her husband, Gregory Rolf, who bought it from a Chinese man in San Francisco, gave Mary the jewel three years ago. The pair are going to stay at Yardly Chase, the home of Lord and Lady Yardly when the moon is next full to discuss the making of a film there and Mary is determined to go with her diamond.