My first case! — with what an agreeable thrill a professional man repeats the words to himself. With most men I believe it is as it was with me, not the case that he intrigues for and expects to get but something quite different, that drops out of Heaven unexpected and undeserved like most of the good things of life. Every now and then in an expansive moment I tell the story of my case, or part of it, whereupon something like the following invariably succeeds: “Why don’t you write it down?” “I never learned the trade of writing.” “But detective stories are so popular!” “Yes, because the detective is a romantic figure, a hero, gifted with almost superhuman keenness and infallibility. Nobody ever accused me of being romantic. I am only an ordinary fellow who plugs away like any other business man. Every day I am up against it; I fall down; some crook turns a trick on me. What kind of a story would that make?” “But that’s what people want nowadays, the real thing, stories of the streets day by day.” Well, I have succumbed. Here goes for better or for worse. Before beginning I should explain that though it was my first case I was no longer in the first bloom of youth. I was along in the thirties before I got my start and had lost a deal of hair from my cranium. This enabled me to pass for ten years older if I wished to, and still with the assistance of my friend Oscar Nilson the wig-maker I could make a presentable figure of youth and innocence.