This is not one of my favorite mysteries by the Queen of Crime. It lacked both drama, and a suitable plot twist. But one thing that I learned on re-reading this novel was the author's methodology. She uses mainly two devices which either help or deter us in solving the crime. First are the various hints which are supposed to lead us to the murderer and are therefore significant. You learn to look out for any seemingly unnecessary stories about characters, or some prolonged conversation which is intended to show us some hidden mystery; but side-by-side to this, we have misleading hints that seem significant, but some part of the information is withheld so that we jump to the wrong conclusion! She, as always, remains superb at misleading, but we eventually realize that the clues were always there to find.
Agatha Christie's characters are never successfully portrayed on television. This is because they are not fully developed, round characters. She has a tendency to stereotype and that is where I think the difficulty arises. Agatha Christie normally categorizes her characters into various types. But people are more than just types, we have to look at them from so many angles and even then we only manage to catch a glimpse. This book had a lot of her normal characterization, for example, we have the typical American couple with the talkative wife and the compliant husband (the same type of talkative American is portrayed in Murder on the Orient Express), we have the quiet, inexpressive Englishman who shows no emotion over the death of his wife, and finally, the nice, slightly pretty wife who has 'brains', a college education and hence no sex appeal!
Nevertheless, some of her characters are unique and fun to read about - I liked the depiction of Arlena Stuart as a man-crazy woman, who was actually to be pitied (read and find out about the reality of her personalty!), and of Rosamund Darnley, a successful business woman, who feels the lack of a husband and children.
Colonel Weston appears in this novel, an old friend of Poirot's, he had previously appeared in the novel Peril at End House. Mrs. Gardiner also mentions one of Poirot's previous cases Death on the Nile. I love the whole illusion of a separate world that Agatha creates with her reappearing characters, and references to old cases.