In the 126 years since his death, Billy the Kid has never stopped inspiring works by our foremost litterateurs, including Larry McMurtry, Michael Ondaatje and Gore Vidal.

Aaron Copland wrote a ballet about him, and he's been the subject of more films than all the presidents of the United States combined, including the French film "Requiem pour Billy the Kid," released in January.

		"BILLY THE KID: THE ENDLESS RIDE" By Michael Wallis Norton ($25.95)

Few figures in American lore have generated so much fiction and fancy, but in Michael Wallis' treatment, he now has a definitive biography.

The facts of William Henry Harrison Antrim's life are sparse. His mother, Catherine, "a jolly Irish lady, full of life," said one acquaintance, died of tuberculosis when Billy was 14. He eventually drifted to Lincoln County, N.M., then the largest county in any state or territory. It also had a homicide rate 47 times higher than the national average.

Billy got mixed up in Lincoln County's political and economic disputes, revenged the killings of his pals and was finally killed himself in 1881. Just about everything else concerning his life is in dispute.

Much more than previous Billy the Kid chroniclers, Wallis (author of "Route 66," "The Real Wild West" and "Pretty Boy: The Life and Times of Charles Arthur Floyd") has succeeded in filling in the background surrounding the enigmatic Billy.

Period witnesses claim he "was a good boy, maybe a little ... mischievous at times," that he was of slight build but blessed with great energy and sharp reflexes, that he was courteous to women and that "his eyes were full of fun."

He might or might not have recited a little poetry; if he didn't, it says something about his power to inspire legend that some thought he did.

Gradually, through Wallis's deft brushstrokes, an image begins to take shape. Dime novels, he writes, particularly appealed to "working class men and boys" such as Billy and his brothers, who were "eager to read about the perils of frontier life ... the pulps featured brigands, renegades, and rogues and transformed them into heroic criminals, driven to their lawless ways by social injustice and the need to defy an oppressive and corrupt establishment."

It appears the soulful young Billy might well have been influenced by the pulp fiction of his time and, in turn, such literature may have colored his contemporaries' impressions of him.

Far from being the common outlaw of countless B movies, Billy's crimes and other killings all seem to have stemmed from personal loyalties.

Wallis finds little evidence for the psychotic killer image depicted in countless fantasies; rather, the Kid became "a convenient target for the Santa Fe Ring and the Dolan Faction," who murdered his friends.

A rather startling fact is that "among the more than fifty individuals indicted for crimes in the Lincoln County War, only the Kid was ever convicted."

That Billy the Kid, under any name, has survived in American cultural memory for so long is due in no small part to his popularity with the Hispanic population of Lincoln County:

"While the Anglo establishments ... propagated the demonic Billy the Kid, many in the Hispanic community cheered him as their hero. To them, he was not a ruthless killer but he was their El Chivato, their little Billy, a champion of the poor and oppressed. He became both the ultimate underdog and a true social bandit."

No matter how the story is told, "Billy the Kid lives on ... His ride across our popular imagination will never end," at least not while "Billy The Kid: The Endless Ride" remains in print.