Holmes was not the first great literary detective-that honor belongs to Edgar Allan Poe's Inspector Auguste Dupin-but Conan Doyle's hero was the most vivid exemplar of the fledgling genre, which Poe dubbed "tales of ratiocination." Holmes is a cold, calculating machine, a man who is, as one critic put it, "a tracker, a hunter-down, a combination of bloodhound, pointer, and bulldog." The gaunt Holmes has no wife or children; as he explains, "I am a brain, Watson. The rest of me is a mere appendix." Rigidly scientific, he offers no spiritual bromides to his bereaved clients. Conan Doyle reveals virtually nothing about his character's interior life; he is defined solely by his method. In short, he is the perfect detective, the superhero of the Victorian era, out of which he blasted with his deerstalker hat and Inverness cape.

Richard read the stories straight through, then read them again. His rigorous mind had found its match in Holmes and his "science of deduction," which could wrest an astonishing solution from a single, seemingly unremarkable clue. "All life is a great chain, the nature of which is known whenever we are shown a single link of it," Holmes explains in the first story, "A Study in Scarlet," which establishes a narrative formula that subsequent tales nearly always follow. A new client arrives at Holmes's Baker Street consulting room. The detective stuns the visitor by deducing some element of his life by the mere observation of his demeanor or dress. (In "A Case of Identity," he divines that his client is a shortsighted typist by no more than the worn "plush upon her sleeves" and "the dint of a pince-nez at either side of her nose.") After the client presents the inexplicable facts of the case, "the game is afoot," as Holmes likes to say. Amassing clues that invariably boggle Watson, the stories' more earthbound narrator, Holmes ultimately arrives at a dazzling conclusion-one that, to him and him only, seems "elementary." In "The Red-headed League," Holmes reveals to Watson how he surmised that an assistant pawnbroker was trying to rob a bank by tunnelling underneath it. "I thought of the assistant's fondness for photography, and his trick of vanishing into the cellar," Holmes says, explaining that he then went to see the assistant. "I hardly looked at his face. His knees were what I wished to see. You must yourself have remarked how worn, wrinkled and stained they were. They spoke of those hours of burrowing. The only remaining point was what they were burrowing for. I walked round the corner, saw the City and Suburban Bank abutted on our friend's premises, and felt that I had solved my problem."

Following the advice that Holmes often gave to Watson, Green practiced how to "see" what others merely "observed." He memorized Holmes's rules, as if they were catechism: "It is a capital mistake to theorize before one has data"; "never trust to general impressions, my boy, but concentrate yourself upon details"; "there is nothing more deceptive than an obvious fact."

Not long after Green turned thirteen, he carried an assortment of artifacts from local junk sales into the dimly lit attic of Poulton Hall. Part of the attic was known as the Martyr's Chamber and was believed to be haunted, having once "been tenanted by a lady, who was imprisoned there and persecuted to death for her religion," according to Hawthorne. Nevertheless, up in the attic, Green assembled his objects to create a strange tableau. There was a rack of pipes and a Persian slipper stuffed with tobacco. There was a stack of unpaid bills, which he stabbed into a mantle with a knife, so that they were pinned in place. There was a box of pills labelled: poison; empty ammunition cartridges and trompe-l'oeil bullet marks painted on the walls ("I didn't think the attic would stand up to real bullets," he later remarked); a preserved snake; a brass microscope; and an invitation to the Gasfitters' Ball. Finally, outside the door of the room, Green hung a sign: baker street.

Relying on the stray details sprinkled throughout Conan Doyle's stories, Green had pieced together a replica of Holmes and Watson's apartment-one so precise that it occasionally drew Holmes aficionados from other parts of England. One local reporter described the uncanny sensation of climbing the seventeen stairs-the same number specified in the stories-as a tape recording played in the background with the sounds of Victorian London: the rumble of cab wheels, the clopping of horses' hooves on cobblestones. By then, Green had become the youngest person ever inducted into the Sherlock Holmes Society of London, where members sometimes dressed in period costumes-in high-waisted trousers and top hats.

Though Holmes had first appeared in print nearly a century earlier, he had spawned a literary cult unlike that of any other fictional character. Almost from his inception, readers latched on to him with a zeal that bordered on "the mystical," as one Conan Doyle biographer has noted. When Holmes made his debut, in the 1887 Beeton's Christmas Annual, a magazine of somewhat lurid fiction, he was considered not just a character but a paragon of the Victorian faith in all things scientific. He entered public consciousness around the same time as the development of the modern police force, at a moment when medicine was finally threatening to eradicate common diseases and industrialization offered to curtail mass poverty. He was the proof that, indeed, the forces of reason could triumph over the forces of madness.

By the time Green was born, however, the worship of scientific thinking had been shattered by other faiths, by Nazism and Communism and Fascism, which had often harnessed the power of technology to demonic ends. Yet, paradoxically, the more illogical the world seemed, the more intense the cult surrounding Holmes became. This symbol of a new creed had become a figure of nostalgia-a person in "a fairy tale," as Green once put it. The character's popularity even surpassed the level of fame he had attained in Conan Doyle's day, as the stories were reenacted in some two hundred and sixty movies, twenty-five television shows, a musical, a ballet, a burlesque, and six hundred radio plays. Holmes inspired the creation of journals, memorabilia shops, walking tours, postage stamps, hotels, themed ocean cruises.

Edgar W. Smith, a former vice-president of General Motors and the first editor of the Baker Street Journal, which publishes scholarship on Conan Doyle's stories, wrote in a 1946 essay, "What Is It That We Love in Sherlock Holmes?":

We see him as the fine expression of our urge to trample evil and to set aright the wrongs with which the world is plagued. He is Galahad and Socrates, bringing high adventure to our dull existences and calm, judicial logic to our biased minds. He is the success of all our failures; the bold escape from our imprisonment.

What has made this literary escape unlike any other, though, is that so many people conceive of Holmes as a real person. T. S. Eliot once observed, "Perhaps the greatest of the Sherlock Holmes mysteries is this: that when we talk of him we invariably fall into the fancy of his existence." Green himself wrote, "Sherlock Holmes is a real character… who lives beyond life's span and who is constantly rejuvenated."

At the Sherlock Holmes Society of London, Green was introduced to "the great game," which Sherlockians had played for decades. It was built around the conceit that the stories' true author was not Conan Doyle but Watson, who had faithfully recounted Holmes's exploits. Once, at a gathering of the elite Baker Street Irregulars (which Green also joined), a guest referred to Conan Doyle as the creator of Holmes, prompting one outraged member to exclaim, "Holmes is a man! Holmes is a great man!" If Green had to invoke Conan Doyle's name, he was told, he should refer to him as merely Watson's "literary agent." The challenge of the game was that Conan Doyle had often written the four Holmes novels and fifty-six short stories-"the Sacred Writings," as Sherlockians called them-in haste, and they were plagued with inconsistencies that made them difficult to pass off as nonfiction. How, for instance, is it possible that in one story Watson is described as having been wounded in Afghanistan in the shoulder by a Jezail bullet, though in another story he complains that the wound was in his leg? The goal was thus to resolve these paradoxes, using the same airtight logic that Holmes exhibits. Similar textual inquiries had already given birth to a related field, known as Sherlockiana-mock scholarship in which fans tried to deduce everything from how many wives Watson has (one to five) to which university Holmes attended (surely Cambridge or Oxford). As Green once conceded, quoting the founder of the Baker Street Irregulars, "Never had so much been written by so many for so few."