A distinguished American writer of fiction said to me lately: "Did you ever think of the vital American way we live? We are always going after mental gymnastics." Now the mystery story is mental gymnastics. By the time the reader has followed a chain of facts through he has exercised his mind,—given himself a mental breather. But the claims of the true mystery story do not end with the general reader. It is entitled to the consideration of the discriminating because it indubitably takes its own place as a gauge of mastery in the field of the short story.