Had she been born in America instead of Germany – or had she emigrated at some point before 1932 – Leni Riefenstahl might have gone down in history as one of Hollywood’s greatest stars.

Tall and strikingly beautiful, with long flowing hair, she was also tenaciously ambitious and wildly talented. When Riefenstahl died at the remarkable age of 101 in 2003, it was said that she remained as ambitious and talented as ever right up to the end.

But in 1932, she was invited to a meeting with Germany’s most famous up-and-coming politician. Seeing him speak for the first time, she later said, was “”like being struck by lightning.”” Riefenstahl, who knew and cared little about politics, was overwhelmed by the power of a speaker who seemed more an “”evangelist”” than a politician.

Walking on the beach with the future leader of Germany, Riefenstahl would never forget the moment when he turned to her and declared: “”Once we come to power, you must make my films.”” Thus Riefenstahl’s fate was etched: She would go down in history as the woman who made the greatest propaganda films of all time – for Adolf Hitler.

With its flashy camera angles and innovative techniques, “”Triumph of the Will”” (1935) was a virtual tone poem to the Nazi Party. Its sinister echoes continue to be felt in everything from music videos to Disney movies. “”Olympia,”” (1938) meanwhile, all but invented the way sports footage is shot. Indeed, Pauline Kael, the most respected film critic of the last century, called them “”the two greatest films ever directed by a woman.””

Steven Bach’s new biography “”Leni”” is probably the most comprehensive biography of Riefenstahl to date. He has made use of archives and interviews with seemingly everyone who ever knew Riefenstahl.

He’s uncovered some startling information, such as the fact that Riefenstahl may have been part Jewish. He readily dismisses rumors that she had an affair with Hitler, but he notes every other affair she ever had (plenty, it turns out).

His tale of Riefenstahl’s 1937 visit to the U.S. is an amusing one. Expecting a grand reception in Hollywood, the young director was instead scorned and ignored – except by Walt Disney, who invited her to his studio and showed her drawings of a Mickey Mouse cartoon in the works. Bach includes a photo of a rather forlorn-looking Riefenstahl decked out in a cowboy hat and boots – one of the most surreal images you’ll ever see.

Bach also writes brisk, readable prose. His book is in some ways an admirable achievement.

But Bach also has an agenda, one that he presses on the reader on nearly every page. He wants to prove that Riefenstahl was a fraud in every sense. Yes, he concedes, Riefenstahl was a great artist, but she was a despicable person; therefore she couldn’t have been a great artist.

He also refers to her as “”Leni”” throughout, in a condescending manner that reeks of cheap sexism. It’s hard to believe he would have referred to Joseph Goebbels as “”Joe”” throughout a biography.

Indeed, Bach makes his distaste for Riefenstahl’s ambitiousness very clear; words like “”narcissism”” and “”self-righteousness”” abound. And the bait is being taken; in a despicable review, critic Richard Schickel sneers: “”Leni Riefenstahl was a slut. Steven Bach is too graceful a writer and too nuanced a psychologist to summarize this life so bluntly, but …”” Need I go on?

There’s no need to let Riefenstahl off the hook. She was all too eager to work for the Nazis and all too eager to forget the dismal consequences once the war was over. After the war, the revelation of what the Nazis had done to millions of people seems to have driven her into a state of deep self-delusion and denial, and she never fully apologized for her role in promoting a vile demagogue’s murderous regime.

But if that were all there were to Riefenstahl, no one would have any reason to read a book about her. Riefenstahl was na’ve and in some ways mendacious; she was also fascinatingly driven – as a young woman, she taught herself to climb mountains barefoot. She remained physically active well into her 90s.

While the book’s subtitle is “”The Life and Work of Leni Riefenstahl,”” Bach does not even include a filmography – a remarkable absence in a book about a world-famous director, and one that seems designed to imply that because of what she did, her work is beneath comment. A damning book could be written about Riefenstahl, but this isn’t the way to do it.