"From the time of our first meetings, I promised myself to follow you everywhere, even in death. You know that my whole life is loving you," Eva Braun wrote to her Führer shortly after July 20, 1944, when a briefcase bomb just missed blowing him up. His clothes torn to shreds, an arm damaged, Adolf Hitler, already enfeebled from lack of exercise and a demonic need to spend long hours micromanaging the war, watched his Nazi cohort abandon him. On his last day in the bunker, few remained, except his personal staff and Braun, who finally became his wife for the last 36 hours of their lives.

The 17-year-old Eva met Hitler in 1929, while working in his official photographer's shop. Like many German women, she had been indoctrinated to seek an all-powerful male leader. Hitler was courteous with women, who in the Nazi scheme of things were intended only to raise strong Aryans while supporting their fathers and husbands. He liked obedient dogs and sentimental songs. He liked to watch Eva dress up in traditional Bavarian costume. He gorged on cream cakes and brought her chocolates. That he was a political figure and found it hard to spare time for her only made him more precious to Braun.

There is no evidence that Braun was anti-Semitic and she never joined the Nazi Party. Hitler never discussed policy with her; indeed, he thought women had no business in public life. He never publicly acknowledged Eva, and even private photographs of them together almost always show him as stiff and formal. She wanted marriage but was willing to wait. He said he belonged to the German people — and that a family would be distracting. In "TheLost Life of Eva Braun" (St. Martin's Press, 512 pages, $29.95), Angela Lambert suggests that because of his belief in eugenics, Hitler dared not pass on defective genes (incest and mental illness were a part of his family history).

Ms. Lambert's biography is verbose. Why does she repeat so many facts? Why do we need to learn several times that Albert Speer was named Hitler's personal architect at 29? What Ms. Lambert explains in a footnote is then explained again in the text and vice versa. Sentences wind back on one another, bloated and redundant: "Eva's tact and sensitivity towards the domestic team were diplomatic, bearing in mind her youth when her position was formalized and the fact that they had no idea how long she would stay."

Other than a few thousand words from a diary Eva kept in the mid 1930s, and her extensive collections of photographs (which Ms. Lambert describes with fascinating precision), most of what is known about Braun comes from her family and friends. Many witnesses thought her superficial, even stupid. But not Ms. Lambert, who finds a nobility and courage in Braun's character — no matter how monstrous the object of her adoration.

But to Eva, Hitler was no monster. Ms. Lambert doubts she knew about the concentration camps and other atrocities Hitler perpetrated. But certainly Eva knew something. To be a sentient human being meant that no matter how cosseted, she had to be aware (especially in the last days) that Hitler had turned Germany into an inferno. Did Eva repress her uneasiness, or project, as Hitler did, the fault onto others? We will probably never know, since it was not her role as a woman to even raise such questions.

Or so Ms. Lambert surmises: "Their true relationship will always be a mystery but at the heart of it may be this: Only with Eva could he step down from his pedestal and allow himself to be dependent, childlike, attached." We simply don't know if this is so, or if this is: "Eva never complained to Hitler about being depressed or lonely." Never?

Ms. Lambert believes that she knows Eva because Eva is like Ms. Lambert's mother, a German woman of Eva's generation who never could come to terms with Hitler and the Holocaust. Ms. Lambert lived in Germany just after the war, and she writes about hearing her mother tell the stories and sing the songs that Eva would have learned.

Some readers may object to the intrusive biographer, but I found the analogies Ms. Lambert draws between her family and Eva's an important way of understanding how she produced such an empathetic portrayal of her subject. This biography has an obsessive quality, a personal tone that allows Ms. Lambert to imagine in depth what it was like for Eva, but which also carries her to a realm closer to fiction than fact.