Robert Oppenheimer had a changeling's face. Seen straight on, he was beguilingly handsome. Seen from the side, he was almost goofy looking. He was slue-footed and a klutz around machines. The contradictions were not superficial: a brilliant physicist who dazzled colleagues with his intellectual improvisations, he often alienated the very people he needed to impress. And while he was notoriously absent-minded, he revealed a genius for administration when he oversaw the development of the atomic bomb in little more than two years. A great American success story, he was also a tragic figure, doomed by many of the qualities that propelled him to fame.

The eldest son in a wealthy Jewish family in New York City, Oppenheimer grew up coddled--his mother wouldn't let him play with other children--and pampered: he didn't go to the barber, the barber went to him. When World War II broke out, this intellectual prodigy was teaching physics at Berkeley and Caltech--and writing checks to left-wing causes. The FBI could never prove that Oppenheimer was a communist; the 10,000 documents in his FBI file show that it wasn't for want of trying.

In Kai Bird and Martin J. Sherwin's definitive biography, "American Prometheus," Oppenheimer is the driving force behind the atom bomb. Appointed director of the project when he was only 42, he marshaled a team of the world's best physicists to build a bomb in record time. Jennet Conant's forthcoming history of that process, "109 East Palace," lovingly details how a boys' school near Santa Fe, N.M., was transformed into a lab said to look like a cross between "an alpine resort and a mining camp."

Los Alamos was a success story with a tragic ending, and one that Oppenheimer, who initially saw nothing wrong with using the bomb on civilian targets, never saw coming. Only after Hiroshima did he comprehend what an awful era he had helped create. In "The Ruin of J. Robert Oppenheimer," which will be published in July, Priscilla J. McMillan details his futile battle against the arms race during the McCarthy era, which ended with the loss of his security clearance and the destruction of his reputation by unscrupulous Red-baiters.

Oppenheimer stands as a hero in these books precisely because the authors, Bird and Sherwin in particular, are so tough on him. He was arrogant and sometimes blindly ambitious. He allowed himself to be caught in lies. Still, he always acted with the interests of his country at heart. And he continues to fascinate us not only because he was a horrific figure but because he embodied one of the big contradictions of American life: he was an idealist who put his faith in science and was then blindsided by dark consequences. Oppenheimer's life does not influence us. It haunts us.