A kaleidoscope of other recollections fills in the fractured gaps. Maurice Nadjari, now 90, the Manhattan prosecutor who pursued the thieves with Javert–like determination, still vividly remembers the case that made his career. Detective Richard Maline dictated his memories in a 50-page oral history, which his widow Barbara passed along to me. Roger Clark, before his death, confided tidbits to family members and friends. Freedom of Information requests produced a trove of yellowing documents from police, prison, and court archives.

Out of touch for many years, Kuhn and Murphy now frequently reminisce with each other, yet memories have a way of shape-shifting. "Allan can't remember anything," complains Murphy, noting that Kuhn has smoked a lot of marijuana. Kuhn shakes his head, saying, "Jack has a need to make every story just a little better."

A childless widower, Kuhn stumbled into a new line of work in 2007. After complaining about insomnia to a local doctor, Kuhn was given a prescription to grow medical marijuana, which was surprising to a man who had done jail time in the late 1960s for possession of a joint. His backyard crop now provides a lucrative livelihood. When I visited, Kuhn had just returned from delivering a batch to Los Angeles clinics, and the house reeked of weed.

While Murphy even has his own Web site touting his role in the museum robbery, Allan Kuhn, by contrast, has spent the intervening decades doing everything possible to be invisible. His phone is unlisted. He lives in a tiny mountain town in Northern California, a winding two-hour drive from a major airport that ends with a few turns down a rutted dirt road to a rustic rental house. Kuhn has not met with a reporter in 40-plus years, and insisted as a condition of our interview that I not reveal the name of his hometown. Photos of Kuhn as a young man highlight his chiseled build and daredevil grin; even now, at age 76, he's in wiry good health and bears a long white ponytail and laidback demeanor. A believer in New Age spirituality, his living room features a shrine with candles, offerings, and photos of U.F.O.s.

Jack Murphy has made being Murf the Surf (his preferred spelling) into a career. A charismatic mile-a-minute talker, Murphy is based near Tampa and makes his living as a prison evangelist, traveling the country—Angola one week, Raiford the next—discussing his rap sheet and urging convicts to find God. In conversation, he is mesmerizingly manipulative—funny and ebullient, then abruptly exuding a hard-edged and menacing persona with a thousand-yard stare. He delights in keeping people off-kilter. "I wasn't always the kindly white-haired grandfather that you see before you now," he says. These days, he goes to comic extremes to convey that he is a law-abiding citizen; the fear of even a parking ticket upsets the former second-story man. "I don't want to get in trouble with the Miami cops," he says. "I've had enough trouble here."

The second and third acts of Murphy and Kuhn's story have equally dramatic arcs. Their sentence completed, the three jewel thieves walked out of prison free and famous—and then made choices that took each of them in radically different directions. The bonds of friendship have frayed, yet the men have been forever bound together by their night at the museum. Roger Clark, the amiable bumbler who served as the lookout, suffered from heart disease and died in 2007, at age 71. But Jack Murphy and Allan Kuhn, once high-living partners in crime, still talk about their good old (bad old) days.

Upon their arrest, the three beach boys taunted and outwitted the authorities. Federal and state prosecutors vied to retrieve the jewels, convening separate grand juries and stealing each other's witnesses. Only after a bizarre series of events—including a Miami chase scene that included Kuhn jumping out a hotel window, double-dealing by a fence, and ransom money paid by one of America's richest businessmen—were most of the jewels eventually recovered. The three beach boys, who pled guilty, spent more than two years at Rikers Island.

Apprehended within 48 hours of the robbery, the two men, plus accomplice Roger Clark, became national folk heroes. With the jewels nowhere to be found, an ambitious 23-year-old Wellesley graduate, Nora Ephron, landed her first front-page story for the New York Post by sneaking into the hotel where the thieves had stayed. "These guys had committed the perfect victimless crime," Ephron recalled in an interview in the fall of 2010. "It was delicious. No one had a clue what they had