The Penrose Mystery

I have been asked to make my contribution to the curious history of the disappearance of Mr. Daniel Penrose, and I accordingly do so; but not without reluctance and a feeling that my contribution is but a retailing of the smallest of small beer. For the truth is that of that strange disappearance I knew nothing at the time, and, even now, my knowledge is limited to what I have learned from those who were directly concerned in the investigation. Still, I am assured that the little that I have to tell will elucidate the accounts which the investigators will presently render of the affair, and I shall, therefore, with the above disclaimer, proceed with my somewhat trivial narrative. ...