"Every woman adores a fascist," Sylvia Plath cried out in her poem "Daddy." "To me, Hitler is the greatest man who ever lived. He truly is without fault, so simple and at the same time possessed of masculine strength," Leni Riefenstahl told a Detroit News reporter in February 1937.

Riefenstahl has often been called the greatest woman documentary filmmaker — although she would have bridled at the "woman." No feminist, she wanted nothing less than her due as a great artist. In her masterpiece, "Triumph of the Will," her documentary film of the 1934 Nuremberg Nazi party rally, Hitler descends out of the clouds in his plane and down to earth. Riefenstahl's cameraman films Hitler standing in his Mercedes touring car, from behind, so that we are watching Hitler from the backseat of his moving vehicle as the dictator gives the fascist salute to crowds of yearning women clamoring for his attention.

The documentary's famous low angle shots enhance Hitler's lofty presence — he is Germany's godlike savior. When he addresses the faithful, he urges them to be obedient, and they respond with joyful assent, affirming what Herman Hess, introducing Hitler to the crowd, makes explicit: Hitler is Germany, and Germany is Hitler.

Seized by the sheer visual power of Riefenstahl's work, viewers across the world surrendered to a spectacle of power, harmonization, and grace. The careful choreography of the Nazi masses, the marching soldiers, the workers lined up with their shovels resting on their shoulders like rifles, reflects the director's dance aesthetic. Never before in film had anyone made a mass political movement look and sound (the music was carefully recorded in a studio) so seductive.

Biographers are perhaps better situated than film critics to fathom the Riefenstahl paradox. New biographies by Jürgen Trimborn (Faber & Faber, 285 pages, $30) and Steven Bach (Knopf, 299 pages, $30) dismantle Riefenstahl's myth that she was an artist innocent of political motivations. Mr. Trimborn had the advantage of observing Riefenstahl close-up during an interview and in subsequent correspondence with her. He found the director to be a consummate protector of her reputation, a careerist of the first order who never wavered in her self-promoting agenda. Meanwhile, Mr. Bach's chapters on Riefenstahl's early career are also valuable since he is the first biographer to have access to a cache of more than 70 interviews with Riefenstahl's friends and co-workers.

Mr. Trimborn's chapter on her anti-Semitism is a shocker. An expert on films of the Nazi era, Mr. Trimborn shows how intricately involved Riefenstahl was not merely with Hitler as he rose to power, but also with Nazis like Jules Streicher, who formulated the party's virulent anti-Semitic program. Mr. Trimborn's book has finally settled the issue of the Goebbels diaries, in which Riefenstahl figures as an artist who understands the party better than anyone and who comes to Goebbels's parties and attends the opera with him and his wife, Magda. Riefenstahl repudiated the diaries, pointing out that that by 1934 Goebbels resented her special relationship with Hitler and tried to interfere with her work. True enough, Mr. Trimborn shows, but he also provides the circumstantial evidence that bolsters Goebbels's portrayal of her as a Nazi enthusiast.

Mr. Trimborn often writes as a film historian. He is primarily interested, for example, in exploring the "pre-fascist" elements of Arnold Fanck's 1920s "mountain films," which featured stunning shots of Riefenstahl climbing mountain peaks in her bare feet. Fanck's romantic exultation of the hero influenced Riefenstahl's portrayal of a heroic Hitler. The Führer, so often at the apex of the crowd scenes in "Triumph of the Will," towers over his followers. Mr. Bach, on the other hand, presents a more dramatic and intimate view of the Fanck/Riefenstahl relationship. His exclusive access to Fanck's own account (recorded by Peggy Wallace in 1974) shows how mesmerizing Franck found Riefenstahl. Her dancing revealed her childlike quality, her surrender to the moment, and this natural, naïve quality made her the perfect heroine for his Alpine love stories. Riefenstahl was involved in a love triangle involving Fanck and her leading man, Luis Trenker, demonstrating, in Mr. Bach's words, "Leni's skill at dominating the exclusive male society in which she found herself now and for almost all the rest of her professional life." She was naïve, in some ways, Mr. Bach implies, but rather cunning in others. Mr. Bach, who is florid compared with the trenchant Mr. Trimborn, provides more personal details and is just as good on Riefenstahl's politics.

In the 1930s Riefenstahl won international awards, although, of course, there were critics who resisted her siren song. As she continued to attract a new generation of film scholars and feminists in the 1970s, the influential Susan Sontag repudiated her earlier endorsement of Riefenstahl and emphasized the director's disturbing politics over her aesthetic: All of Riefenstahl's work celebrated power and elevated strength and the body beautiful over all other values. This "fascist aesthetic" permeated Riefenstahl's work as an actress in her popular 1920s films and, most famously, in her documentary, "Olympia," about the 1936 Olympic games, hosted by Hitler in Berlin. And yet her film work remains a potent model. Mr. Trimborn, for example, points out that the "Olympic Portraits" (1996), shot by Sontag's life partner, Annie Leibovitz, reveals evidence of Riefenstahl's influence.

Riefenstahl's own archive remains closed, and even though Mr. Trimborn believes it includes only self-serving material, that, too, may be more illuminating than Mr. Trimborn supposes. As good as these two biographies are, no one fascinated with Riefenstahl can forgo studying Ray Muller's revelatory film, "The Wonderful, Horrible Life of Leni Riefenstahl," which allows the director to make her case even as her behavior confirms her latest biographers' findings. ( )