Freeman Wills Crofts, The Cask. Dorothy Sayers: Whose Body? Earl Derr Biggers, The House without a Key. Agatha Christie, The Murder of Roger Ackroyd. Patricia Wentworth, Grey Mask. Dashiell Hammett, Red Harvest. Gladys Mitchell, Speedy Death. Mignon Eberhart, The Patient in Room 18. Margery Allingham, Mystery Mile. Dorothy Sayers, Strong Poison.