With this preface I come to the death of Arthur Wells, our acquaintance and neighbor, and the investigation into that death by a group of six earnest people who call themselves the Neighborhood Club. ***** The Neighborhood Club was organized in my house. It was too small really to be called a club, but women have a way these days of conferring a titular dignity on their activities, and it is not so bad, after all. The Neighborhood Club it really was, composed of four of our neighbors, my wife, and myself. We had drifted into the habit of dining together on Monday evenings at the different houses. There were Herbert Robinson and his sister Alice--not a young woman, but clever, alert, and very alive; Sperry, the well-known heart specialist, a bachelor still in spite of much feminine activity; and there was old Mrs. Dane, hopelessly crippled as to the knees with rheumatism, but one of those glowing and kindly souls that have a way of being a neighborhood nucleus. It was around her that we first gathered, with an idea of forming for her certain contact points with the active life from which she was otherwise cut off. But she gave us, I am sure, more than we brought her, and, as will be seen later, her shrewdness was an important element in solving our mystery. In addition to these four there were my wife and myself. It had been our policy to take up different subjects for these neighborhood dinners. Sperry was a reformer in his way, and on his nights we generally took up civic questions. He was particularly interested in the responsibility of the state to the sick poor. My wife and I had “political” evenings. Not really politics, except in their relation to life. I am a lawyer by profession, and dabble a bit in city government. The Robinsons had literature. Don’t misunderstand me. We had no papers, no set programs. On the Robinson evenings we discussed editorials and current periodicals, as well as the new books and plays. We were frequently acrimonious, I fear, but our small wrangles ended with the evening. Robinson was the literary editor of a paper, and his sister read for a large publishing house. Mrs. Dane was a free-lance. “Give me that privilege,” she begged. “At least, until you find my evenings dull. It gives me, during all the week before you come, a sort of thrilling feeling that the world is mine to choose from.” The result was never dull. She led us all the way from moving-pictures to modern dress. She led us even further, as you will see. On consulting my note-book I find that the first evening which directly concerns the Arthur Wells case was Monday, November the second, of last year.