"The Mystery of the Blue Train" is a detective novel by Agatha Christie, featuring her famous Belgian detective Hercule Poirot. It was first published in 1928. Here are some key points about the novel:Plot: The story revolves around the murder of American heiress Ruth Kettering, who is found dead in her compartment on the Blue Train, a luxury train traveling from London to the French Riviera. Poirot, who happens to be on the same train, takes on the case to uncover the killer.Characters: Besides Hercule Poirot, the novel features his friend Katherine Grey, who becomes...