One word more. Of all the affairs pursued by the two Queens this, which Ellery has titled “The Roman Hat Mystery” for reasons shortly to be made clear, was surely the crowning case of them all. The dilettante of criminology, the thoughtful reader of detective literature, will understand as the tale unfolds why Ellery considers the murder of Monte Field worthy of study. The average murderer’s motives and habits are fairly accessible to the criminal specialist. Not so, however, in the case of the Field killer. Here the Queens dealt with a person of delicate perception and extraordinary finesse. In fact, as Richard pointed out shortly after the dénouement, the crime planned was as nearly perfect as human ingenuity could make it. As in so many “perfect crimes,” however, a small mischance of fate coupled with Ellery’s acute deductive analyses gave the hunting Queens the single clue which led ultimately to the destruction of the plotter. J. J. McC. New York, _March 1, 1929._ LEXICON OF PERSONS CONNECTED WITH THE INVESTIGATION Note: The complete list of individuals, male and female, brought into the story of Monte Field’s murder and appended below is given solely for the convenience of the reader. It is intended to simplify rather than mystify. In the course of perusing mysterio-detective literature the reader is, like as not, apt to lose sight of a number of seemingly unimportant characters who eventually prove of primary significance in the solution of the crime. The writer therefore urges a frequent study of this chart during the reader’s pilgrimage through the tale, if toward no other end than to ward off the inevitable cry of “Unfair!”—the consolation of those who read and do not reason. E. Q. Monte Field, an important personage indeed—the victim. William Pusak, clerk. Cranially a brachycephalic. Doyle, a _gendarme_ with brains. Louis Panzer, a Broadway theatre-manager. James Peale, the Don Juan of “Gunplay.” Eve Ellis. The quality of friendship is not strained. Stephen Barry. One can understand the perturbation of the juvenile lead. Lucille Horton, the “lady of the streets”—in the play. Hilda Orange, a celebrated English character-actress. Thomas Velie, Detective-Sergeant who knows a thing or two about crime. Hesse, Piggott, Flint, Johnson, Hagstrom, Ritter, gentlemen of the Homicide Squad. Dr. Samuel Prouty, Assistant to the Chief Medical Examiner. Madge O’Connell, usherette on the fatal aisle. Dr. Stuttgard. There is always a doctor in the audience. Jess Lynch, the obliging orangeade-boy. John Cazzanelli, _alias_ “Parson Johnny,” naturally takes a professional interest in “Gunplay.” Benjamin Morgan. What do you make of him? Frances Ives-Pope. Enter the society interest. Stanford Ives-Pope, man-about-town. Harry Neilson. He revels in the sweet uses of publicity.