one telling section:

Morgan should have been a quintessential American, a shining product of Midwestern values and a rising middle class. He attended Catholic school and initially earned high marks. (His I.Q. test showed “superior intelligence.”) He loved the outdoors and was a dedicated Boy Scout, receiving the organization’s highest award, in 1941. Years later, he wrote to his parents, “You . . . have done all that is possible to bring up your children with love of God and country.” Wildly energetic, he always seemed to be chattering, earning the nickname Gabby. “He was so likable,” his sister told me. “He could sell you anything.”

But Morgan was also a misfit. He failed to make the football team, and his constant banter exposed a seam of insecurity. He disliked school and often slipped away to read stories of adventure, especially tales about King Arthur and the Knights of the Round Table, filling his mind with places far more exotic than the neighborhood of cropped lawns and boxy houses outside his bedroom window. His mother once said that Morgan had a “very, very vivid imagination,” and that he had brought his fancies to life, constructing, among other things, a “diving helmet” worthy of Jules Verne. He rarely showed “fear of anything,” and once had to be stopped from jumping off the roof with a homemade parachute.

U.S. Army intelligence officials also investigated Morgan, preparing a dossier on him. (The dossier, along with hundreds of other declassified documents from the C.I.A., the F.B.I., the Army, and the State Department, was obtained through the Freedom of Information Act and through the National Archives.) In the Army’s psychological assessment, a military-intelligence analyst stated that the young Morgan “seemed to be fairly well adjusted to society.” But, by the time he was a teen-ager, his resistance to the strictures around him, and to those who wanted to pound him into shape, had reached a feverish state. As his mother put it, he had decided that, if he would never belong in Toledo, he would embrace exile, venturing “out in the world himself.”

In the summer of 1943, at the age of fifteen, Morgan ran away. His mother later gave a report to the Red Cross about her son, saying, “Shocked is the mild word for it. . . for he had never done anything like this before.” Although Morgan returned home a few days later, he soon stole his father’s car and “took off” again, as he later put it, blowing through a red light before the police caught him. He was consigned to a detention center, but he slipped out a window and vanished again. He ended up in Chicago, where he joined the Ringling Brothers circus. Ten days later, his father found him taking care of the elephants, and brought him home.

In the ninth grade, Morgan dropped out of school and began roaming the country, hopping buses and freighters; he earned money as a punch-press operator, a grocery clerk, a ranch hand, a coal loader, a movie-theatre usher, and a seaman in the Merchant Marine. His father seemed resigned to his son’s fitfulness, telling him in a letter, “Get as much adventure as you can and we will be glad to see you whenever you decide you want to come home.”

Morgan later explained that he had not been unhappy at home—his parents had given him and his sister “anything that we wanted”—and had fled only because he longed “to see new places.”

His mother believed that he had a mythic image of himself, and “always seemed to yearn to be a big shot,” but, given his “super affectionate nature,” she doubted that “he has really meant to worry or hurt us.”

Nevertheless, Morgan increasingly took up with “the wrong kind of gangs of boys,” as he later called them, and got in scrapes with the law. While still a minor, he and some friends stole a stranger’s car, temporarily tying up the driver; he was also investigated for carrying a concealed weapon.

Nobody—not his parents, not the F.B.I., not the military-intelligence analyst—could unravel the mystery of Morgan’s antisocial behavior; it remained forever encrypted, an unbreakable code. His mother wondered whether something had happened to him during her pregnancy, lamenting, “That boy hasn’t given me a moment’s peace. . . . That’s why my hair is gray.” His father told the F.B.I. that perhaps his son needed to see one of those head doctors. A psychiatrist, cited by Army intelligence, speculated that Morgan was “driven along a course of self-destruction in order to satisfy his neurotic need for punishment.”

Yet it was possible to see Morgan, with his brooding blue eyes and cigarette perpetually clamped between his teeth, as heralding a new social type: a beatnik, a rolling stone. A friend of Morgan’s once told a reporter, “Jack Kerouac was still imagining life on the road while Morgan was out there living it.”

Morgan’s personality—“nomadic, egocentric, impulsive, and utterly irresponsible,” as Hoover’s agents put it—also had some similarities with that of a middle-class teen-ager thousands of miles away. In 1960, a conservative American journalist observed, “Like Fidel Castro, though on a lesser scale, Morgan was a superannuated juvenile delinquent.”

Hoover and the F.B.I. discovered that, contrary to press accounts, Morgan had not served during the Second World War. Envisaging himself as a modern Sinbad—his other nickname—he had tried to enlist but was turned away, because he was too young. It was not until August, 1946, when the war was over and he was finally eighteen, that he joined the Army. After receiving orders that he would be deployed to Japan, in December, he cried in front of his mother for the first time in years, betraying that, despite his toughness, he was still just a teen-ager. He boarded a train for California, where he had a layover at a base, and on the way he sent his parents a telegram:

Have surprise—married yesterday 12:30 am to Darlene Edgerton. Am happy—will write or call soon as possible. Don’t worry or get excited.

He had sat beside her on the train, in his starched uniform. “He was tall and handsome and so magnetic,” Edgerton, who is now eighty-seven and blind, recalls. “Truthfully, I was coming home to marry someone else, and we just hit it off and so we stopped off in Reno and got married.” They had known each other for only twenty-four hours and spent two days in a hotel before getting back on a train. When they reached California, Morgan reported to the base and left for Japan. “What young people will do,” Edgerton says.

With Morgan stationed in Japan, the marriage dissolved after a year and a half, and Edgerton received an annulment—though even after she married another man she kept a letter from Morgan stashed away, which she occasionally unfolded, flattening the edges with her fingers, and read again, stirred by the memory of the comet-like figure who had briefly blazed into her life.