The Golden Age of Detective Fiction became a period in which the greatest authors saw the story as an attempt bt the writer to foll the reader, and many of them had their own methods in doing so. […] Christie specialized in the Least Likely Suspect gambit, and it was amazing the number of changes she was able to ring on that single theme. She was the mistress of the unexpected (but obvious when revealed) motive, of creating a character who seems to play one role while actuallt playing another – in short, of authorial legerdemain. As Jonh Dickson Carr pointed out, Agatha Christie was like a magician who could make the reader look one place while she calmly palmed the ace.
It all began with The Mysterious Affair at Styles.