Missing, presumed dead, for three years, Sherlock Holmes returns triumphantly to his dear companion Dr Watson. And not before time! London has never been in more need of his extraordinary services: a murderous individual with an air gun stalks the city.Among thirteen further brilliant tales of mystery, detection and deduction, Sherlock Holmes investigates the problem of the Norwood Builder, deciphers the message of the Dancing Men, and cracks the case of the Six Napoleons.It was in the spring of the year 1894 that all London was interested, and the fashionable world dismayed, by the murder of the Honourable Ronald Adair under most unusual and inexplicable circumstances. The public has already learned those particulars of the crime which came out in the police investigation; but a good deal was suppressed upon that occasion, since the case for the prosecution was so overwhelmingly strong that it was not necessary to bring forward all the facts. Only now, at the end of nearly ten years, am I allowed to supply those missing links which make up the whole of that remarkable chain. The crime was of interest in itself, but that interest was as nothing to me compared to the inconceivable sequel, which afforded me the greatest shock and surprise of any event in my adventurous life. Even now, after this long interval, I find myself thrilling as I think of it, and feeling once more that sudden flood of joy, amazement, and incredulity which utterly submerged my mind. Let me say to that public which has shown some interest in those glimpses which I have occasionally given them of the thoughts and actions of a very remarkable man that they are not to blame me if I have not shared my knowledge with them, for I should have considered it my first duty to have done so had I not been barred by a positive prohibition from his own lips, which was only withdrawn upon the third of last month.It can be imagined that my close intimacy with Sherlock Holmes had interested me deeply in crime, and that after his disappearance I never failed to read with care the various problems which came before the public, and I even attempted more than once for my own private satisfaction to employ his methods in their solution, though with indifferent success. There was none, however, which appealed to me like this tragedy of Ronald Adair. As I read the evidence at the inquest, which led up to a verdict of wilful murder against some person or persons unknown, I realised more clearly than I had ever done the loss which the community had sustained by the death of Sherlock Holmes. There were points about this strange business which would, I was sure, have specially appealed to him, and the efforts of the police would have been supplemented, or more probably anticipated, by the trained observation and the alert mind of the first criminal agent in Europe. All day as I drove upon my round I turned over the case in my mind, and found no explanation which appeared to me to be adequate. At the risk of telling a twice-told tale I will recapitulate the facts as they were known to the public at the conclusion of the inquest.The Honourable Ronald Adair was the second son of the Earl of Maynooth, at that time Governor of one of the Australian Colonies. Adair's mother had returned from Australia to undergo the operation for cataract, and she, her son Ronald, and her daughter Hilda were living together at 427, Park Lane. The youth moved in the best society, had, so far as was known, no enemies, and no particular vices. He had been engaged to Miss Edith Woodley, of Carstairs, but the engagement had been broken off by mutual consent some months before, and there was no sign that it had left any very profound feeling behind it.