A Man Lay Dead is a detective novel by Ngaio Marsh; it is the first novel to feature Roderick Alleyn, and was first published in 1934. The plot concerns a murder committed during a detective game of murder at a weekend party in a country house. Although there is a side-plot focused on Russians, ancient weapons, and secret societies, the murder itself concerns a small group of guests at Sir Hubert Handesley's estate.