By S.S. Van Dine, a pseudonym for art critic and detective novelist Willard Huntington Wright. First published in The American Magazine in September 1928.
The detective story is a kind of intellectual game. It is more — it is a sporting event. And for the writing of detective stories there are very definite laws — unwritten, perhaps, but none the less binding; and every respectable and self-respecting concocter of literary mysteries lives up to them. Herewith, then, is a sort Credo, based partly on the practice of all the great writers of detective stories, and partly on the promptings of the honest author’s inner conscience.
Read more via Twenty Rules for Writing Detective Stories | Aerogramme Writers’ StudioTwenty Rules for Writing Detective Stories.