The mystery story is a kind of writing that need not dwell in the shadow of the past and owes little if any allegiance to the cult of the classics. It is a good deal more than unlikely that any writer now living will produce a better historical novel than Henry Esmond, a better tale of children than The Golden Age, a sharper social vignette than Madame Bovary, a more graceful and elegant evocation than The Spoils of Poynton, a wider and richer canvas than War and Peace or The Brothers Karamazov. But to devise a more plausible mystery than The Hound of the Baskervilles or The Purloined Letter should not be too difficult. Nowadays it would be rather more difficult not to.

Introduction - The Simple Art of Murder (1950)