The Red Widow Murders
John Dickson Carr
 An oddly assorted group of people draw cards to see who will spend the night locked into a room said to be haunted by the "Red Widow" -- a legendary figure who was married to the executioner who guillotined French aristocrats. In the morning, the victim is found dead, locked inside a room whose door was continuously under observation. He has been poisoned by curare, which must be absorbed into the body through a break in the skin, but no wounds of any kind are found on the body. Henry Merrivale must solve the mystery.