Agatha Christie still manages to fascinate, over 40 years after her death. Her home in Devon is a popular tourist attraction, The Mousetrap continues to play in London – 64 years and counting – and her fictional detectives are household names. Crime novelist Sophie Hannah has even been writing new Hercule Poirot mysteries, while Andrew Wilson, another enthusiast, contributes this first of a new series in which Agatha Christie herself is the protagonist. He uses a real-life mystery from 1926: the author’s 10-day disappearance and subsequent reappearance in a Harrogate hotel, claiming amnesia.