"The Case of the Missing Will" by Agatha Chrisite

　　Mr. Marsh asks the workmen to make a cavity beneath the fireplace and hides his partially burnt second will there. This is to distract Poirot’s investigation. Poirot infers that Mr. Marsh has made a third will. He finally finds it in the form of an envelope attached to the Key of Roll Top Desk. 　　I do not understand why the words on the envelope were written in a crabbed handwriting. Nor do I understand why Poirot recognizes that the envelope is the will. 　　Christie first sets the conclusive key, and comes back to the beginning of the story by inserting several twists and turns. And finally the reader reads an extraordinary event at the outset of the story. This is one of her techniques of making detective stories. --------------------------------- [beginning] The problem presented to us by Miss Violet Marsh made rather a pleasant change from our usual routine work. Poirot had received a brisk and businesslike note from the lady asking for an appointment, and had replied asking her to call upon him at eleven o’clock the following day. . . . . [ending] Always employ the expert. She has amply proved her right to the money” I wonder—I very much wonder—what old Andrew Marsh would have thought!