Nazis, implying that the events of The Labours of Hercules took place after 1937. Another alternative would be to suggest that the Preface to the Labours takes place at one date but that the labours are completed over a matter of twenty years. None of the explanations is especially attractive. In terms of a rudimentary chronology, Poirot speaks of retiring to grow marrows in Chapter 18 of The Big Four (1927) which places that novel out of published order before Roger Ackroyd. He declines to solve a case for the Home Secretary because he is retired in Chapter One of Peril at End House (1932). He has certainly retired at the time of Three Act Tragedy (1935) but he does not enjoy his retirement and repeatedly takes cases thereafter when his curiosity is engaged. He continues to employ his secretary, Miss Lemon, at the time of the cases retold in Hickory Dickory Dock and Dead Man's Folly, which take place in the mid-1950s. It is, therefore, better to assume that Christie provided no authoritative chronology for Poirot's retirement but assumed that he could either be an active detective, a consulting detective, or a retired detective as the needs of the immediate case required. One consistent element about Poirot's retirement is that his fame declines during it so that in the later novels he is often disappointed when characters (especially younger characters) recognise neither him nor his name: "I should, perhaps, Madame, tell you a little more about myself. I am Hercule Poirot." The revelation left Mrs Summerhayes unmoved. "What a lovely name," she said kindly. "Greek, isn't it?" Post–World War II Poirot is less active during the cases that take place at the end of his career. Beginning with Three Act Tragedy (1934), Christie had perfected during the inter-war years a subgenre of Poirot novel in which the detective himself spent much of the first third of the novel on the periphery of events. In novels such as Taken at the Flood, After the Funeral, and Hickory Dickory Dock, he is even less in evidence, frequently passing the duties of main interviewing detective to a subsidiary character. In Cat Among the Pigeons, Poirot's entrance is so late as to be almost an afterthought. Whether this was a reflection of his age or of Christie's distaste for him, is impossible to assess. Crooked House (1949) and Ordeal by Innocence (1957), which