Kareem Abdul-Jabbar Illustration by Tom Bachtell

Kareem Abdul-Jabbar walked through the lobby of his hotel on Central Park South recently, doing his best impression of someone with a low profile. He swerved to avoid a chandelier (low clearance for a former N.B.A. center), then bumped into an old friend who’d been a coach with the Chicago Bulls. Handshakes, camera flashes. Finally, Abdul-Jabbar wriggled free. “I have somewhere to be,” he said, adjusting a white cashmere scarf over his blue pin-striped suit. He ducked through a doorway, took a few loping steps to the curb, and scrunched into the back of a black Suburban.

He was late for cocktails at the Yale Club, where the Baker Street Irregulars, an eighty-one-year-old Sherlock Holmes society, was hosting its annual dinner. Abdul-Jabbar—a Sherlockian since he began reading Sir Arthur Conan Doyle as a rookie with the Milwaukee Bucks, in 1969—was making his inaugural appearance. Earlier that week, Abdul-Jabbar had announced that he would soon publish his first novel, “Mycroft Holmes,” a thriller about Sherlock Holmes’s older brother. Conan Doyle’s Mycroft is old and haggard, “world-weary,” Abdul-Jabbar said. “We want to see how he was before he took his lumps from the slings and arrows of outrageous fortune.”

The car crept through midtown, and Abdul-Jabbar said, “I’m curious just to see who these people are.” He did an impression of Jonny Lee Miller, the latest incarnation of Sherlock Holmes, on the CBS show “Elementary.” “I am not a nice man. I am acerbic. I get things done in my style,” he said, in a plummy English accent.

Abdul-Jabbar was raised in Harlem, but he lives in Los Angeles. “I first read these books on the beach in San Diego when we were playing the Rockets,” he said. “Holmes saw clues where other people saw nothing.” From then on, he imagined himself as a courtside sleuth. He recalled going up against Manute Bol, one of the tallest players in N.B.A. history. “He was the only guy I had to look up to. So I figured out his weaknesses,” he said. “I make deductions. That’s what I do. Hey, I read Sherlock Holmes.” In the Holmes stories, the Baker Street Irregulars are a group of street urchins who pass along intelligence to the detective. Abdul-Jabbar lifted tips from ball boys. One time, he heard them complaining about how Bob Lanier—the six-foot-eleven Moriarty of the Detroit Pistons—would sneak cigarettes during halftime. “I knew, if Lanier was smoking, if I made him run in the second half he’d be in pain,” he said. “These are the little clues I pick up.”

Abdul-Jabbar walked into the Yale Club. “I’m here for Holmes,” he told a bewildered doorman, who waved him to an elevator. On the twentieth floor, he entered a ballroom, where two hundred people were holding highballs and exchanging arcana about their man. In Conan Doyle’s day, the Sherlockians drove the author to the edge of madness. He once tried to kill off Holmes to keep the fanatics at bay.

On a table by the entrance were nametags: King of Bohemia, The Red Circle, Kareem Abdul-Jabbar. Society members have their own aliases, or “investitures,” culled from the Holmes stories. “These used to all be story titles, but we ran out,” said Leslie Klinger (Abbey Grange), the editor of a Holmes anthology and Abdul-Jabbar’s attorney. “One of the investitures is Smack, Smack, Smack,” he said, after a bug-squashing character in the story “The Adventure of the Copper Beeches.” Klinger, who wore a tuxedo, tried to whisper into his client’s ear but wound up shouting: “Kareem, there’s someone here who wants you to do a podcast about Mycroft!” Abdul-Jabbar was being accosted by Inspector Baynes, whose alias refers to a character from the Surrey Constabulary, and Vincent Spaulding, named for one of Conan Doyle’s criminals. “The Bucks need you,” a Sherlockian from Oshkosh pleaded with Abdul-Jabbar, before staggering away. The Irregulars meet only once a year, and their exuberance showed.

Corporal Henry Wood offered an outstretched hand and asked Abdul-Jabbar about his novel. “It all started with a book called ‘Enter the Lion,’ Mycroft’s posthumous memoir,” he said. Corporal Henry Wood knew it well. “But of course, edited by my dear friend. A great book. Preach on!” Then the Corporal pulled out a selfie stick and waved it up toward Abdul-Jabbar. “Mind if we take a photo?”

“What is that contraption?” Abbey Grange asked.

“I guess it was inevitable,” Abdul-Jabbar said, more of the stick than of the selfie. Holmes wasn’t one for gadgetry.

Dinner was announced, and the Irregulars repaired to the dining room, two floors below, where the Sherlockian rites would commence. There would be a toast to Dr. Watson’s second wife, a reading from “The Adventure of the Musgrave Ritual,” and a tribute to the society’s fallen members, in an installment called “Stand with Me Here Upon the Terrace.” Secrets had to be kept. With a nod, Abdul-Jabbar strode off to the back stairway. ♦