“Until about 1957, Agatha Christie's plots were ingeniously composed of interlocking segments. This was the area in which she excelled; her tone and style have always been less satisfactory. The former is often whimsical or sententious, the latter unremittingly bland. She was involved in the delineation of a world of safety and complacence where the precise moment of a misdeed could be established by reference to an unfailing custom.”

Source: Wikiquote