 By accepting the date given in "The Chocolate Box" over later novels, which never gave precise ages anyway, it can be explained why Poirot is around for so long.Also the debate over Poirot’s family is fuelled mainly by the fact that he mentions a sister in the original publication of "The Chocolate Box" but for some reason this reference was removed from the later editions.The Poirot books are still under copyright in the United Kingdom.