In 1999, the Croatian novelist Slavenka Drakulić visited The Hague to observe the trials for war crimes committed in the former Yugoslavia. Among the defendants was Goran Jelisić, a thirty-year-old Serb from Bosnia, who struck her as “a man you can trust.” With his “clear, serene face, lively eyes, and big reassuring grin,” he reminded Drakulić of one of her daughter’s friends. Many of the witnesses at The Hague shared this view of the defendant—even many Muslims, who told the court how Jelisić helped an old Muslim neighbor repair her windows after they were shattered by a bomb, or how he helped another Muslim friend escape Bosnia with his family. But the Bosnian Muslims who had known Jelisić seven years earlier, when he was a guard at the Luka prison camp, had different stories to tell. Over a period of eighteen days in 1992, they testified, Jelisić himself killed more than a hundred prisoners. As Drakulić writes, he chose his victims at random, by asking “a man to kneel down and place his head over a metal drainage grating. Then he would execute him with two bullets in the back of the head from his pistol, which was equipped with a silencer.” He liked to introduce himself with the words “Hitler was the first Adolf, I am the second.” He was sentenced to forty years in prison.

Arendt in a Paris café, in 1935. Her celebration of the public realm was matched by a mistrust of the private realm. To her, the personal was emphatically not political. Photograph by Hannah Arendt Bluecher Literary Trust

None of Drakulić’s experience in creating fictional characters could help her understand such a mind, which remained all the more unfathomable because of Jelisić’s apparent normality, even gentleness. “The more you realize that war criminals might be ordinary people, the more afraid you become,” she wrote. What Drakulić discovered, in other words, is what Hannah Arendt, at the trial of Adolf Eichmann, in Jerusalem, some forty years earlier, called “the fearsome, word-and-thought-defying banality of evil.” Drakulić titled her book “They Would Never Hurt a Fly,” after Arendt’s description of a typical Nazi functionary who “does not regard himself as a murderer because he has not done it out of inclination but in his professional capacity. Out of sheer passion he would never do harm to a fly.” Arendt’s concept has become so famous that it is hard to remember how bitterly controversial it was when she first used it. Many readers resisted what looked like an attempt to trivialize the Nazis. “No banality of a man could have done so hugely evil a job so well,” one critic wrote. Yet even those who dispute Arendt’s judgment acknowledge her influence on the way we think about political evil. As long as ordinary people can be transformed overnight into mass murderers, we are still living in Hannah Arendt’s world.

It is an ambiguous tribute to Arendt, then, that her scholarly and popular profile is higher today than at any time since she died, in 1975, at the age of sixty-nine. In the past few years, a number of Arendt’s works have been published by Schocken Books, where she worked as an editor in the nineteen-forties. “The Origins of Totalitarianism” has been accompanied by several collections of essays—most notably “The Jewish Writings,” edited by Jerome Kohn and Ron Feldman, which includes Arendt’s wartime journalism. Scholars around the world have kept pace with a torrent of studies—on Arendt and international relations, Arendt and human rights, Arendt and the Jewish question. It is hard to name another thinker of the twentieth century more sought after as a guide to the dilemmas of the twenty-first.

Yet it is not just political theorists who find Arendt a source of fascination. The most intense curiosity about Arendt in the past few years has had less to do with her work than with her life. Above all, the publication in English, in 2004, of Arendt’s correspondence with Martin Heidegger, after decades of speculation about their relationship, brought renewed scrutiny to her intimate life. To a thinker who believed that the personal was emphatically not political, this kind of attention would have been very unwelcome. She derided the “pseudoscientific apparatuses of depth-psychology, psychoanalysis, graphology, etc.” as nothing more than “curiosity-seeking.” Yet Arendt’s deeply ambivalent relationship with Heidegger—her lover, teacher, and friend—has a more than personal significance, since it casts light on the most vexed issue in her work: her tangled relationship with Jewishness and Germanness.

Arendt’s legend—or, perhaps it is better to say, her image—has become as important to posterity as her theories. In part, of course, this is because Arendt is one of the few women in the traditionally male pantheon of political philosophy. It makes sense that it is feminist readers who find the most food for thought in Arendt’s image—even though Arendt denied that she was a feminist. Julia Kristeva devotes some pages of her recent book on Arendt to her changing appearance, as documented in photographs: from the girlish “seductress” of the nineteen-twenties, gazing poetically at the camera, to the confident intellectual of the fifties, whose “femininity . . . beats a retreat” as her face becomes “a caricature of the . . . battle scars” received during her public career.

Kristeva’s reverie on Arendt’s “psychic bisexuality” is not the kind of attention that gets paid to Kant or Heidegger. Yet it is a sign of the way that Arendt has emerged as something both more and less than a political theorist. The most rewarding way to read Arendt, and the best way to make sense of both the strengths and the limitations of her work, is to approach her as Michelle-Irène Brudny does in “Hannah Arendt: An Essay in Intellectual Biography”: “I definitely take Hannah Arendt to be less a political philosopher or a political theorist . . . than an author in the strong sense of the word.” Kristeva, still more emphatically, considers Arendt’s writings “to be less a body of work than an action.” Like so many Jewish writers of her generation, Arendt attempted in her work to shine the light of intellect on the extreme darkness she lived through. That she chose to do this in the most impersonal of genres—philosophy and history—rather than through memoir, or even poetry (which she loved to read, and wrote from time to time), is itself a clue to the immense psychological pressures that shaped her work and, in the end, partly disfigured it.

The power of the impersonal is the great theme of Arendt’s work, and it is no coincidence that she first discovered it in the most literary, least theoretical of her books, “Rahel Varnhagen: The Life of a Jewess.” It was the first book she wrote (not counting her doctoral dissertation), but it was not published for almost two decades, and it remains, even today, a kind of orphan in the Arendt canon. Readers of “Eichmann in Jerusalem” and “The Origins of Totalitarianism” tend to ignore this impressionistic biography of a late-eighteenth-century hostess and letter writer, whose Berlin salon was one of the breeding grounds of German Romanticism. Yet the Rahel biography, as Kristeva says, is “a veritable laboratory of Arendt’s political thought.”

Arendt acknowledged her deep affinity with Rahel Varnhagen, née Levin, calling her “my very closest woman friend, unfortunately dead a hundred years now.” What they had in common was their predicament as highly gifted Jewish women in a culture that exacted a terrible psychic toll both on women and on Jews. In Berlin, at the time of the French Revolution, Rahel’s friends included some of Prussia’s greatest minds. They were drawn to her freedom from social convention, and to the exquisite sensibility that informed her cult of Goethe, her extensive correspondence, and her love affairs. Yet during the Napoleonic Wars, as Prussian nationalism began to flourish, many of Rahel’s German friends deserted her; her Gentile fiancé, whom she saw as her ticket to respectable society, refused to marry her. She was left alone with her inwardness, mourning “the thing which all my life seemed to me the greatest shame, which was the misery and misfortune of my life—having been born a Jewess.” Not until she was dying did she decide that, all the same, Jewishness was the one thing “I should on no account now wish to have missed.”

When Arendt first discovered Rahel, in the late nineteen-twenties, she recognized her as both a tutelary spirit and a cautionary tale. Arendt was born in 1906, into a family that, like so many German Jewish families, ardently pursued Rahel’s ideal of culture, or Bildung. “With us from Germany,” she wrote bitterly during the Second World War, “the word ‘assimilation’ received a ‘deep’ philosophical meaning. You can hardly realize how serious we were about it.” Again like Rahel, Arendt was conspicuous for her intelligence from an early age; as a young woman, she was nicknamed Pallas Athene. When, in 1924, she went to Marburg University, she entered into the study of theology and philosophy as into her own inheritance, even though she recognized that they might be uncomfortable subjects for a Jew. When she signed up for a seminar on the New Testament, she sternly warned the professor, Rudolf Bultmann, that “there must be no anti-Semitic remarks.”

Yet Arendt could not have suspected just how fraught her encounter with philosophy would turn out to be. Like all the most enterprising students, she enrolled in a class with Martin Heidegger. Heidegger was then at work on his magnum opus, “Being and Time,” but already he had a reputation as a thrilling teacher. As Arendt remembered a lifetime later, in her tribute to Heidegger on his eightieth birthday, “Little more than a name was known, but the name made its way through all of Germany like the rumor of a secret king.” She was thus more than prepared to respond when the married, thirty-five-year-old professor began to fall in love with her.

The fact that Heidegger and Arendt were lovers was no secret to her close friends—“Oh, how very exciting!” Karl Jaspers exclaimed when Arendt told him—and it has been public knowledge since Elisabeth Young-Bruehl revealed it in her 1982 biography. But the affair became a kind of highbrow scandal in 1995, when Elzbieta Ettinger, a professor at M.I.T., wrote about it in a short book, “Hannah Arendt / Martin Heidegger.” Ettinger, who had been granted access to the Heidegger-Arendt correspondence for the purpose of writing a new biography of Arendt, instead made it the subject of a sensational exposé. The book was loftily derided by Arendtians; yet, without the curiosity that Ettinger excited, it is doubtful that Arendt’s and Heidegger’s estates would have consented to the publication of their letters, which cast a fascinating new light on this most important chapter in Arendt’s life.

The correspondence, which is collected in “Letters 1925-1975,” is revealing, first of all, in its very incompleteness. Arendt kept all of Heidegger’s letters, from the very beginning; he kept few of hers, and none from the early years. As a result, Heidegger’s voice dominates the book, just as his personality and his decisions dominated the affair. As one would expect, Heidegger—an older male professor, who also happened to be one of Europe’s greatest philosophers—treats his teen-age lover with a combination of passion and condescension. He is capable of poetic raptures: “The demonic struck me. . . . Nothing like it has ever happened to me,” he writes not long after their first meeting. Yet while Arendt’s intellect helped draw him to her, he is deeply patronizing about her intellectual ambitions. He urges her to take a “decisive step back from the path toward the terrible solitude of academic research, which only man can endure,” and to concentrate instead on becoming “a woman who can give happiness, and around whom all is happiness.”

Understandably, after a year of covert meetings and emotional confrontations, Arendt left Marburg for Heidelberg, where, in Jaspers, she found a more equable teacher. It is just possible to glimpse in the letters the pain that the affair caused Arendt—above all, by enforcing a sense of powerlessness. Early on, in an autobiographical composition addressed to Heidegger and titled “Shadows,” Arendt described herself in the third person: “Her sensitivity and vulnerability, which had always given her an exclusive air, grew to almost grotesque proportions.” As late as 1929, when Arendt ran into Heidegger at a train station and for a moment he failed to recognize her, she found the experience shattering: “When I was a small child, that was the way my mother once stupidly and playfully frightened me. I had read the fairy tale about Dwarf Nose, whose nose gets so long nobody recognizes him anymore. My mother pretended that had happened to me. I still vividly recall the blind terror with which I kept crying: but I am your child, I am your Hannah.—That is what it was like today.”

The full significance of her experience with Heidegger did not unfold, however, until the early nineteen-thirties. As the Weimar Republic collapsed and Nazi violence grew, Arendt began to hear unsettling rumors about Heidegger’s sympathy with National Socialism. Her letter to him on the subject is lost, but we can gauge her anxiety from Heidegger’s response, which is tentatively dated “Winter 1932/33.” “The rumors that are upsetting you are slanders,” he begins, and proceeds to give an evasively technical defense of his treatment of Jewish students and colleagues. (If he refused to supervise a Jewish student’s dissertation, he explains, it was only because “I am on sabbatical this winter semester”; and, besides, “the man who, with my help, got a stipend to go to Rome is a Jew.”) Nowhere in the letter is there any denial of Nazi sympathies. Instead, Heidegger simply assures Arendt that, whatever happens, “it cannot touch my relationship to you.” After reading this letter, Arendt could not have been entirely surprised when, in 1933, Heidegger joined the Nazi Party and became the rector of Freiburg, with the mission of aligning the university with the new party-state.