An occasion and an envoi. There are many interesting facts surrounding this book; it has been accorded the highest price ever paid by a paperback house--$925,000; it was also written in the early '40's and Mrs. Christie originally specified that it was not to appear until after her death--one of those vagaries, like her mysterious disappearances? However we now have the last Hercule Poirot returning to the scene of his Mysterious Affair at Styles. Styles has since become a seedy guest house for "twilit people" and there are many ruminations about euthanasia which anticipate our time. From the beginning, Poirot, arthritically cribbed in a wheelchair, confides to his old friend Hastings that there is an X factor at Styles--responsible for five unaffiliated demises with more to come now, by inference, by indirection. Of course Poirot has all this prefigured (whereas Hastings, and Mrs. Christie's duller readers may not) before his last beau geste. How can it remain unrecognized?