It may seem somewhat counterintuitive, but actually makes sense when you're familiar with the history of female crime fiction. While most of the credit for breaking off from Golden Age orthodoxy goes to the very male-driven hardboiled school and some British mavericks like Anthony Berkeley or Richard Hull, the truth is that female writers did more than their share to bring up the change, and sometimes initiated it. Mrs. Belloc Lowndes or Elizabeth Sanxay Holding dispensed with the puzzle plot (which most hardboiled writers, starting with Hammett and Chandler, kept adhering to) long before the likes of Francis Iles and James M. Cain; and the arcane plots of hardboiled fiction and psychological suspense can be traced to the early twentieth century work of Mary Roberts Rinehart. Writers most comparable to Christie in terms of approach, plotting and virtuosity are almost all males - Ellery Queen, John Dickson Carr, even S.S. Van Dine. The other so-called crime queens (Allingham, Marsh, Sayers, some would add Mitchell and Tey) were typically less interested in orthodox puzzle plotting, deception and more likely to "push the envelope". (As a matter of fact, Sayers or Allingham are today more celebrated as "literary" writers than detective writers) So I think Rivière had a point, though I disagree that following in Christie's steps is a bad thing and a sign of backwardness. I like mysteries that "push the envelope" (don't say "transcend the genre"!) but I also like some orthodoxy; it may even be more challenging. Breaking the rules is easy; expressing one's personality while following them is much harder and far more rewarding.
