[Gil Troy teaches history at McGill University. His most recent book is titled "Hillary Rodham Clinton: Polarizing First Lady."]

When urban cowboys condemn rap music's celebration of violence, they overlook the celebrity outlaws peppering the Western tradition. Billy the Kid, Jesse James and other desperadoes still captivate Americans, more than a century after they terrorized citizens and occasionally killed lawmen. Even today, long after the supposed death of the Western, black hat myth-making remains big business. Over the decades, hundreds of books and comic books, television shows and movies have told the tales and enhanced the legends of the Western gunslinger. By unraveling the mystery of one, can we discover their hold on us all?

The Western author and PBS host Michael Wallis certainly believes that Billy the Kid's story can unlock broader secrets of the American psyche. The author of the best-selling "Route 66" and a book about another charming bandit, Pretty Boy Floyd, Wallis valiantly sifts through the conflicting accounts of the Kid to "present a clear, concise, and truthful story of a young man who became a legend in his time."

Wallis believes the story of this "romanticized youth" can explain America's "culture of violence," while the fluctuations in his standing reflect wavering American attitudes regarding the disparity between the rich and poor, the establishment's credibility and the ubiquity of corruption. Billy the Kid has been praised as a crusader for justice, a modern-day Robin Hood for Hispanics. He has been pitied as a victim, buffeted by the post-Civil War South's social dislocation, crushed by the lawless and corrupt powers that dominated the Gilded Age Southwest. And he has been feared as a "bloodthirsty man-killer, a homicidal maniac." In fact, Wallis laments in one of his most colorful lines, "There has never been much middle ground when it comes to judging Billy the Kid, just black and white with scant gray to calm the palette."

The Kid was the famous -- or infamous -- teenage bandit, who roamed America's Southwest. His short career was abbreviated by the single-action .44 Colt pistol the legendary sheriff Pat Garrett fired on the night of July 14, 1881. He died before reaching his 22nd birthday.

He has lived on, however, portrayed in more than 50 movies by Roy Rogers, Paul Newman and Emilio Estevez, among others. Writers fascinated by the Kid include Zane Grey, Gore Vidal and Michael Ondaatje. Woody Guthrie, Billy Joel, Bob Dylan, and Jon Bon Jovi all sang about him; Aaron Copland wrote the music for a ballet about him. Googling "Billy the Kid" generates 1.4 million hits.

Wallis, however, downplays the contemporary myth-making machine. He plays the historical detective, assessing the elusive facts of his subject's life. Wallis is thorough, cautious, sometimes to a fault. The book teeters on the edge between a salutary judiciousness and pedantic tediousness; there is so much hemming and hawing in the text, not the footnotes, some chapters read like the transcript of a Hedgers Anonymous meeting.

Still, especially, in the book's second half, the narrative gallops ahead, as Billy the Kid plunges into the violence that makes his life story so compelling. If his life had a turning point, it occurred in September 1875, in Silver City, N.M., when Billy was arrested for hiding and for wearing the clothing that an older criminal stole from the local Chinese laundry. Until then, 16-year-old Henry Antrim -- who was probably born in New York City -- was a rambunctious but relatively law-abiding orphan whose Irish-born mother had recently died of tuberculosis (they'd moved West hoping the climate would improve her condition). He had never known his father, and his stepfather had no interest in caring for him.

After two days in jail, the slender youth shimmied up a narrow chimney hole. Covered in soot, he went to a kindly woman who was his surrogate mother. She shipped him off to Arizona, where his stepfather had settled. After the stepfather told him to scram, the teenager spent the next two years traipsing around the mining camps, gambling, stealing horses and working as a saddle tramp.

By late 1876 -- the same year Custer died at Little Big Horn, Wild Bill Hickok was killed and the members of the James gang, save Jesse, were shot up -- Antrim's antics had earned him the sobriquet The Kid or Kid Antrim. "Kid was the common nickname for juveniles of the delinquent variety or at least teenagers who were handy with guns," Wallis reports. He would only be christened Billy the Kid in 1881, the last year of his life.

By 1877, on the lam after murdering at least one man, and yet another daring escape, Kid Antrim was living in the New Mexico Territory's Lincoln County. The looming war there between ranch-hands and the proprietors of the biggest general store would be the setting for his ascension into popular culture immortality. Wallis writes: "Against a backdrop of ethnic hostility, greed, and corruption ... Lincoln County epitomized the desires of the lawless. Crooked politicians, ruthless cattle lords, and hired gunmen cohabited there in a milieu of unspeakable cruelty and vindictiveness." The Kid indulged in all the available sins, except that apparently he rarely smoke or drank.

The ruthless, pointless war between the Kid's faction, the Regulators, and their rivals made Billy the Kid a legend. His significance emerged not "from the part he played in the war, but for the standing he achieved in American folklore." The bloody battle was manna for America's emerging pulp fiction industry. Editors delighted in singling out Billy the Kid, as the boldest, toughest, baddest bad guy. His youth, charm, marksmanship, derring-do, his colorful moniker and his daredevil escape from the Lincoln County Jail -- along with the corpses he left behind -- transformed him into a Western pop star.

Still, despite his reputation, the Kid was more troubled teen than heartless killer. The most surprising twist for those weaned on the legend of Billy the cruel is how frequently the Kid tried to go straight. He repeatedly negotiated an amnesty with Lew Wallace, the governor of the territory who would earn fame for writing "Ben Hur." Clearly, the absence of a firm guiding hand made the lure of all those Western vices irresistible to this wayward youth.

With his deliberate, careful approach, Wallis leaves the reader aware of the gap between The Kid's exploits and the fanciful and often more brutal adventures journalists, novelists and screenwriters would concoct. But the outlaw's allure remains more assumed than explained. The most interesting aspect of Billy the Kid's life begins where the book ends, when he dies but his immortal legend is born as his exaggerated exploits become epic and iconic.

On one level, it is easy to see why passionate characters lacking impulse control would appeal to a nation of desk-jockeys, laptop warriors living vicariously through computer monitors and television screens. Yet Americans seem more dazzled by these myths than Europeans, who are equally desk-bound and technology-addled. These celebrity bad guys' continuing appeal reflects a grittiness and volatility encoded in the American DNA. Remember, our country was founded in Revolution and settled by iconoclastic individualists. Wallis' interesting, crisp book is welcome for feeding our fascination with Billy the Kid and his comrades, even if it does not fully explain this defining, enduring American obsession.