In this version, young Leo wasn't marginalized at all. He was a happy white teenager in a John Hughes movie. ''I had my Camaro,'' he said, ''and hot-looking girlfriends, and we lived in this upper-middle-class suburb with a manicured lawn. People treated each other decently.'' This version of his past was an idealized one, Felton once admitted, but he explained that he couldn't help it: when he was in prison, he said, ''the idea of white culture became symbolic to me. I mythologized it.''

Felton's transformation -- what he called ''the circuitous route I took to becoming 'white,' in quotation marks'' -- started, he said, as soon as he arrived in prison. He spent the first two years of his sentence in New York City, first in the Brooklyn Correctional Facility and then on Riker's Island. What he encountered there was a prison culture that was violent and frightening and racially segregated. Whites were in the minority and felt threatened. ''This was not a game,'' he said. ''Guys were dying. It was a very serious situation. There was definitely a siege mentality among whites.''

Felton began to extrapolate from the black prisoners around him to black culture at large. What he was seeing on Riker's Island, he decided, was the true face of black America, and he concluded that it was nothing like his own face. He stopped telling people about his black father, and he found that his fellow inmates just assumed he was white. He belonged, he decided, on the white side of the prison's color divide. ''The only people that I had anything in common with all happened to be white,'' he said. ''We were surrounded on all sides by an antagonistic alien presence. We stuck together.''

Looking back on the teasing he'd received as a child, he found himself taking the side of his tormentors. ''I began to see the marginalization that I had experienced as a kid as a natural thing,'' he said. ''All forms of life on this planet have an inborn affinity to things that are similar and an aversion to those that are dissimilar.'' He stopped blaming the racists who had antagonized him in his youth. Instead, he blamed his parents, not for being neglectful or cruel but for transgressing against the laws of nature.

It was easy for Felton to convince himself that his evolving racist beliefs were innate and instinctive, even fundamentally human. But that didn't satisfy him. Despite the fact that he never graduated from high school, Felton is in many ways an intellectual, and he wanted to be able to intellectualize his own racial anxiety, to find a coherent philosophy that could let him understand his own place in the divided racial world that he saw around him. He is a man who likes arguments and diatribes and doesn't like being wrong, and he wanted to be able to build an airtight case, with citations and footnotes, for his racist beliefs.

Felton began reading pamphlets and magazines distributed by contemporary American fascist groups, and he read the writings of Adolf Hitler and various Nazi ideologues. But he couldn't escape one crucial fact in those racist doctrines: race, for them, was a biological fact. Felton, to those writers, and to most of the racists with whom he had begun to correspond and associate, was indisputably black (whatever his appearance) and thus part of an inferior race, someone to be shunned. It was a situation that seemed to Felton not so much ontologically wrong as simply unfair. ''I had an investment in these ideas that most people in the movement didn't have,'' he said, ''despite their blond hair and blue eyes.''

Then in 1995 he discovered a book that offered him a way out: ''Imperium,'' a strange work of philosophy and occult religion written just after World War II by an American fascist named Francis Parker Yockey. ''The main thing to understand in Yockey's idea of race,'' Felton explained to me in a letter, ''is that he considered it to have its center of gravity in the spirit rather than in biology. He considered the National Socialist'' -- or Nazi -- ''concept of race to be a product of 19th-century materialism.'' The quote from ''Imperium'' that Felton was most eager to draw to my attention was this one: ''Race is, in the first instance, what a man feels.''