Bernard Capes, The Skeleton Key — Introduction by G. K. Chesterton (1919)
“ The detective or mystery tale, in which this last book is an experiment, involves in itself a problem for the artist, as odd as any of the problems which it puts to the policeman. A detective story might well be in a special sense a spiritual tragedy; since it is a story in which even the moral sympathies may be in doubt. A police romance is almost the only romance in which the hero may turn out to be the villain, or the villain to be the hero. ”
