The man who elucidated the mystery and brought to a close that palimpsest of horror was, curiously enough, in no way officially connected with the police; and in all the published accounts of the murder his name was not once mentioned. And yet, had it not been for him and his novel methods of criminal deduction, the heinous plot against the Greene family would have been conclusively successful. The police in their researches were dealing dogmatically with the evidential appearances of the crime, whereas the operations of the criminal were being conducted on a plane quite beyond the comprehension of the ordinary investigator. This man who, after weeks of sedulous and disheartening analysis, eventually ferreted out the source of the horror, was a young social aristocrat, an intimate friend of John F.-X. Markham, the District Attorney. His name I am not at liberty to divulge, but for the purposes of these chronicles I have chosen to call him Philo Vance. He is no longer in this country, having transferred his residence several years ago to a villa outside of Florence; and, since he has no intention of returning to America, he has acceded to my request to publish the history of the criminal cases in which he participated as a sort of _amicus curiæ_. Markham also has retired to private life; and Sergeant Ernest Heath, that doughty and honest officer of the Homicide Bureau who officially handled the Greene case for the Police Department, has, through an unexpected legacy, been able to gratify his life’s ambition to breed fancy wyandottes on a model farm in the Mohawk Valley. Thus circumstances have made it possible for me to publish my intimate records of the Greene tragedy. A few words are necessary to explain my own participation in the case. (I say “participation,” though, in reality, my rôle was that of passive spectator.) For several years I had been Vance’s personal attorney. I had resigned from my father’s law firm—Van Dine, Davis & Van Dine—in order to devote myself exclusively to Vance’s legal and financial needs, which, by the way, were not many. Vance and I had been friends from our undergraduate days at Harvard, and I found in my new duties as his legal agent and monetary steward a sinecure combined with many social and cultural compensations. Vance at that time was thirty-four years old. He was just under six feet, slender, sinewy, and graceful. His chiselled regular features gave his face the attraction of strength and uniform modelling, but a sardonic coldness of expression precluded the designation of handsome. He had aloof gray eyes, a straight, slender nose, and a mouth suggesting both cruelty and asceticism. But, despite the severity of his lineaments—which acted like an impenetrable glass wall between him and his fellows—, he was highly sensitive and mobile; and, though his manner was somewhat detached and supercilious, he exerted an undeniable fascination over those who knew him at all well.