Published 100 years ago, Agatha Christie's first detective novel takes place during the First World War. The idea of the Christie world as essentially timeless and hermetic has perhaps been exaggerated, with its English country house setting, closed group of well-to-do suspects with plausible motives, a changed will, multile red herrings and drawing-room revelations of 'whodunnit'. The Mysterious Affair at Stykes can be seen as the blueprint for the 'cosy crime' genre, as well as the novel that launched the crime-fighting partnership: Poirot and Hastings.