To her biographer, Simone de Beauvoir confided a less than rhapsodic one-night stand, in 1946, with the Hungarian malcontent Arthur Koestler: “One night I got so drunk I let him come home with me. We slept together. It wasn’t any good. It didn’t mean anything. He was too drunk, so was I. It never happened again. Only that night was real, the rest is how I loathed him.” Beauvoir was rather kinder in Force of Circumstance, the third volume of her memoirs, recalling K.’s curiosity and generosity as well as his self-importance: “Touchy, tormented, greedy for human warmth, but cut off from others by his personal obsessions.” And rather more ambivalent in that plum-pudding roman à clef, The Mandarins, where her alter ego, Anne, will notice, almost immediately after succumbing to the “Slavic charm” of the Koestler-like Scriassine, “a lot of hate” in those “fiery eyes,” and the delusion that “loneliness can be cured by force.”

They got around like a virus or the clap, those European intellectuals. Nor did they fail to ideologize their sadness in the sack (Kronstadt! Slansky!). So delirious, in fact, were the bistro behaviors of The Second Sex and Darkness at Noon, not to mention The Myth of Sisyphus, Nausea and Man’s Fate, that we are tempted to linger and to wallow. Imagine Jean-Paul Words so drunk over onion soup at Les Halles that he fills up paper napkins with pepper and salt and hides them in his pockets. Or Darkness and Sisyphus getting into a fistfight, not because Camus was having it off with K.’s main squeeze, Mamaine “The Mermaid” Paget, but because Caligula accused Scum of the Earth of cheating to win their wager on who could scuttle the fastest across the Place St. Michel on all fours. Or Being and Nothingness calling off their friendship because Invisible Writing insisted on remaining buddies with Voices of Silence, which oracular Silence, André Malraux, had been pressuring Gallimard to cease publication of No Exit’s favorite magazine, Les Temps modernes. And maybe “Mermaid” Paget needs a biography of her own. While The God That Failed was knocking her about–before and after The Stranger ran away with her–Jean-Paul Saint Genet also made a clumsy pass, and so did that Dead Sea Scroll at the Finland Station, Edmund Wilson, while he was still married to The Group.

But if we are to believe David Cesarani’s weird book, Beauvoir was luckier than many of K.’s bedmates. What might just as easily have happened is Koestler’s inviting himself into her flat, bullying her into batching up an omelet, helping her to towel the plates, grabbing her by her hair or throat, pulling her down to the linoleum, banging her head a couple of times and then raping her, after which explaining: “I thought you had a bit of a yen for me.” This is what he did to Jill Craigie, the filmmaker wife of Labor MP Michael Foot. (Craigie died late last year, but not before the details of her interview with Cesarani made headlines in the British tabloids.) And probably what he did to a fair number of other young women in his long career of sexual conquest. It certainly bears a striking resemblance to the “seduction” of Odette by Slavek in his Lisbon novel, Arrival and Departure. More than a user, Koestler was an abuser–of women, alcohol, automobiles and ideas.

This abusiveness–and the evidence is overwhelming that he was an “intemperate, obsessive, egomaniacal, bullying, petty, selfish, arrogant, lecherous, duplicitous and self-deluding” “serial rapist” addicted late in life to “happy pills” (Dexedrine)–is one of two main accusations in a relentless bill of indictment. The other is “the negativity of his Jewishness,” by which Cesarani, a professor of modern Jewish history at Southampton University, means more than ambivalence but a denial verging on self-hatred: “At odds with his origins, uneasy with himself and unable to settle because with no clear identity it was not clear where he belonged, he was condemned to a nomadic life-style. Homelessness became his domicile, and his politics were the politics of location and dislocation.”

Cesarani can’t quite bring himself to link these impeachments–to suggest that Koestler was depraved because he was deracinated; that not only couldn’t he stay put geographically or ideologically but also he drank too much, cracked up cars, punched up cops and raped women, all because he was running away from his Jewishness. This would require actually thinking about other homeless Jewish minds in an era that specialized in forcible evictions and what K. himself once called “stepfatherlands.” Albert Einstein? Herbert Marcuse? Jacques Derrida and Algeria? Elias Canetti and his mother? It’s worth recalling that when Freud finally got permission to leave Vienna in 1938, the Gestapo obliged him to sign a certificate saying that he had been well treated by the authorities. He added a sentence of his own: “I can heartily recommend the Gestapo to anyone.”

Still, Jewish self-hatred is an odd charge to level against the ex-Zionist, ex-Communist and original Cold Warrior, perhaps our pre-eminent parajournalist of totalitarianism and surely the ultimate waffle on the twentieth-century grid–with score marks on his thick hide to prove it from Hitler, Franco and Stalin–who made no secret of his origins in four autobiographies. Who worked part time for the Jewish National Fund and joined a Jewish dueling fraternity at the University of Vienna. Who accompanied the Zionist firebrand Vladimir Jabotinsky on a speaking tour of Austria and Czechoslovakia in 1924 and then to the World Zionist Congress in 1925. Who dropped out of college and shipped off to Palestine in 1926, where for the next three years he flunked kibbutzing, sought in Tel Aviv to start a cabaret, settled in Jerusalem to string for publications in Budapest and Cairo, concocted the first Hebrew crossword puzzle and covered the Middle East for the Ullstein newspaper chain, until they promoted him to Paris. Who returned in 1944 after writing one novel, Arrival and Departure (1943), which even Cesarani admits is “almost the only work of fiction published in Britain during the war, or even after the war, to register the catastrophe” of the Holocaust, to research another, Thieves in the Night (1946), that endorsed Stern Gang terrorism. And who made one last 1948 trip to the fledgling State of Israel, where, like so many other Revisionists, he seemed to hate almost everything about Ben-Gurion’s “totalitarian Lilliput,” including the fact that his jeep was commandeered at gunpoint by Moshe Dayan’s 89th Battalion, after which he published an account, Promise and Fulfillment (1949), that called quits to his love affair with the Promised Land–although he would have gone back in 1967, at Teddy Kollek’s personal request, if not for the Six-Day War. According to Cesarani:

Once Koestler had decisively rejected the realisation of his Jewish identity through Zionism he deliberately cultivated a cosmopolitan, de-Judaised image in his autobiographical writing. The break with Jewishness and Zionism, which is flagged at the end of Promise and Fulfillment, began a process of repression that inflected all his subsequent activities.

Which repression would explain why, for instance, he was so ulterior as to fail to mention that he was Jewish in a 1961 speech to the Royal Society of Literature–about a trip to India and Japan! But not, perhaps, his motivation in taking time off from his chats with Kingsley Amis about ESP to write The Thirteenth Tribe (1976). This eccentric foray into Jewish history argued–from scraps of the tenth-century Arab geographer Muqaddasi and the Byzantine historian Constantine Porphyrogenitus; dialogues in The Kuzari, a dreamy theological tract by the Jewish poet/philosopher of Moorish Spain, Judah Halevi; conflicting reports by sundry Hebrew, Persian, Syrian and Armenian sources; and meditations on such fragments by modern scholars like Toynbee, Bury, Dunlop and the perplexed Hungarian Marxist Antal Bartha–that the Jews of Eastern Europe were actually Khazars, descended from a Caucasian tribe of Turkish stock that thrived more than a thousand years ago between the Black Sea and the Caspian, whose king, court and military caste inexplicably converted to Judaism in AD 740 and then, 200 years and a Russian invasion later, vanished into the speculative mists. Those mists, insisted Koestler, were Hungary, Poland, Lithuania, Crimea and Ukraine. Thus the primary victims of the Holocaust weren’t really Jewish, at least genetically. So much for a Chosen People.

Some of us took The Thirteenth Tribe to be on a par with Koestler’s other enthusiasms of the raffish seventies, like levitation, psychokinesis, catastrophism, Tories and canines. But Cesarani sees a more sinister subtext–“a deep, personal reason for this bizarre exercise”:

he was prepared to go to extraordinary lengths to prove that he was not a Jew, or at least a Jew of the ‘seed of Abraham.’ Koestler could not simply renounce Judaism: he was not a believing Jew and, in any case, saw Jewishness as more than a mere creed–it was a national identity. Indeed, it was even more than that: it was a package of acquired characteristics, a racial type. Given his geneticist convictions the only way he could emancipate himself from the ‘seed of Abraham’ was by tracing his lineage to the loins of the Khazar tribesmen.

Well, maybe. On the other hand, maybe not. “There is nothing more easily falsified than the unconscious,” Italo Calvino has explained. Cesarani only got into the private papers at the Edinburgh Library by promising to write a book about “Koestler’s Jewish identity and themes in his life and work.” So he has to blow this bagpipe every other chapter or look like a magpie. But imagine his surprise at all that date-rape stuff–and the commensurate dismay of Michael Scammell, whose authorized biography, as yet unfinished, is now pre-empted. Likewise pre-empted, one supposes, are the revelations about Koestler’s activities as a Comintern agent in Spain and elsewhere, as faithfully recorded in the suddenly leaky archives of the KGB. Of another famous renegade, the Rilke-reading translator of Bambi, Whittaker Chambers, Koestler himself would remark: “Such peculiar birds are found only in the tree of the revolution.”

Except for his self-help encyclopedias on sex, which Cesarani says weren’t bad for their nervous times, I have read all of Arthur Koestler’s books, beginning with The Invisible Writing when I was 15 years old, and it was as thrilling as Look Homeward, Angel, Catcher in the Rye and Thomas Merton’s Seven-Storey Mountain. Do I like him less, now that I know so much from Cesarani about his piggy personal behavior? Of course. But looking back, it seems to me it was never the man I admired, anyway. It was the career, and the way he wrote about that career, in the saddle as it were, like Isaac Babel in Red Cavalry, or as if, like Trotsky and the mill workers in St. Petersburg, we ducked under the bellies of the horses at a friendly Cossack wink. I wanted to be a cowboy, too, in this extreme western.

Koestler’s great gift, in fact, was to remember the excitement of ideas in action, and to refresh that memory with language, never cheating on the original exaltation no matter how many times he rewrote the events of his life as a yogi, lotus, robot, commissar, call girl or the ghost in his own machine–and Cesarani has counted them all, every revised word, in search of “stupendous act[s] of deception.” In these pages, we are reacquainted with exactly what it felt like to read Karl May and Jules Verne, listen to Lehar operettas and wait for the football scores as a child in Budapest; to discover Rilke, Heine, Hölderlin, Strindberg, Ibsen and Hamsun as a precocious adolescent, as well as Darwin and Kepler; to experience both a revolution (Bela Kun) and a counterrevolutionary terror (Admiral Horthy) at age 13; to fall in love, as a student in Vienna, with Einstein, Bohr, Heisenberg, Adler and Jung; to look for a cause in Palestine, a brothel in Paris, a job in Berlin, the future in Bokhara, Samarkand and Tashkent (with a laid-back Langston Hughes as his companion), and the North Pole from a graf zeppelin; to hobnob with Wilhelm Reich, Karl Radek, André Malraux, Alfred Döblin, Ignazio Silone, George Orwell, Thomas Mann, Dylan Thomas, Cafe Flor phenomenologists, Left Book Club social democrats, Congress for Cultural Freedom-Fighting Partisan Reviewers and even Timothy Leary, who tripped him out on acid; to fear death in a Franco prison (while reading John Stuart Mill in Spanish) and then again in a French DP camp (where Walter Benjamin slipped him some morphine); and to be unbelieved when he told everybody about the Final Solution and the Gulag.

To be sure, the novels were romans à these, too anal in their schematizing. But they were also true to the mythomaniacs who inhabited them. Whether, for instance, the Old Bolshevik Rubashov in Darkness at Noon was based on Bukharin or not, or even whether Bukharin really confessed at his own Show Trial, the case for revolution has seldom been better made, by a writer who had come to revile that revolution. Peter, in Arrival and Departure, leaves Portugal for almost certain death, in spite of a Jungian psychoanalysis by Sonia that not only persuades the reader of the childhood origins of his unconscious guilt but persuades Peter, too–and even the Nazi who goes on about the mineral veins of Europe as a sort of central nervous system is allowed to be more eloquent than any other Nazi I’m aware of in any other antifascist novel. Like Koestler on his first trip to Palestine, Joseph in Thieves in the Night may have his doubts about a collective run on a woozy amalgam of the principles of Tolstoy and Marx, but we see him as well through the eyes of the Communards, in all his vanity, impatience and disdain for manual labor. The Age of Longing (1951), alas, was worse than ugly, it was smug–“To imitate the past and to abolish the past are equal sins against life,” smirked Monsieur Anatole; “therefore all reactionaries suffer from constipation and all revolutionaries from diarrhea”–but at least he got to do to Beauvoir what she had done to him. By the time he dialed up The Call Girls two decades later, he had lost this passionate knack and was reduced to ventriloquism, even if the dummies included W.H. Auden and Konrad Lorenz. Still, it had been a long run for a novelist of rambunctious ideas.

And over all this hectic activity, this compulsive curiosity and headlong rush to covenant, peril and repentance, these big ideas slapped on like adhesive plasters to the wounds of self and the bigger discrepancies for which no poultice ever proved medicinal, he’d spritz promiscuous metaphors and Homeric myth. It was as if, by literary fiat, in chapters of escapade with such headings as “From the Mount of Olives to Montparnasse,” “Liberal Götterdämmerung” and “The Return of Ahor,” he could aggrandize his only childhood, his “emotional measles” and traumatic tonsillectomy, his father’s selling of radioactive soap and his mother’s ever-so-convenient migraines, his “bridge-burning,” vagabondage and violent divestitures, into a “language of destiny,” an “invisible writing” and an “oceanic feeling,” a “third order” and a “parallel universe” of “wonder rabbis,” helpful shamans and wax-winged effigies of Icarus–into which Blue he shot his Arrow.

This was thrilling, too, like modern art and teen sex.

It is possible to forgive Cesarani his misspellings of Nicola Chiaromante as “Nicolas,” of James Fenimore Cooper with an extra “n,” and of the philosopher Zeno as “Xeno” (twice: a Greek paradoz?); his risible description of Henry and Clare Boothe Luce as “pillars of the American liberal establishment”; and even his tricking up of a shaky thesis with the usual pomoblab about “marginality,” “contingency,” “inter-textuality” and “deterritorialised identities”–but not his tin ear for the work itself while he purses prim lips at erotic adventurism; not when he’s tone-deaf in the middle of so much symphonic noise. Koestler may have come to distrust “the great nineteenth-century narratives of progress,” but every bassoon note of that century’s Romantic afflatus resounded in his prose and head. And for all his disenchantment, he’d still maintain:

In the 1930s conversion to the Communist faith was not a fashion or a craze–it was a sincere and spontaneous expression of an optimism born of despair: an abortive revolution of the spirit, a misfired Renaissance, a false dawn of history. To be attracted to the new faith was, I still believe, an honorable error. We were wrong for the right reasons.

I seem alone among my peer group to have kept on reading him through his “pilgrim’s regress” into astronomy, ethnology, brain theory, parapsychology and mysticism–The Sleepwalkers, The Act of Creation, The Ghost in the Machine, Drinkers of Infinity, The Case of the Midwife Toad and The Roots of Coincidence. The Kepler material was terrific, and Creation at least contained a lot of jokes. But the more K. disappeared into subatomic particles and “supra-galactic spaces,” the less persuasive he became, arguing science by random analogy, citing anecdotes as proofs, picking and choosing among half-grasped experiments on a frantic bias, buying into both neo-Lamarckian fantasies of inherited memory and J.B. Rhine’s spoon-bending down at paranormal Duke, infatuated with prime numbers and flatworms, going almost Zen on us with his “holons” and his “hierarchies,” prematurely sociobiologizing–instead of Communism, a “cosmic consciousness”; instead of comradeship, a “collective mind” and “disincarnate mental energy”; instead of dialectical materialism, “bisociation,” a mating of “matrices” along “integrative gradients”; instead of revolution, self-transcendence and the death wish, better living through modern chemistry and super enzymes (a pill to pacify the limbic “crocodile” in our old reptilian brains).

To his credit, Cesarani slogs through all this, when you know he’d really rather talk some more about the many abortions Koestler foisted on his “masochistic” wives and groupies, the daughter he refused to see, his “pathological need to wander,” his “pathological promiscuity” and his “feeble” attempts at suicide–before, of course, fed up with Parkinson’s and lymphatic leukemia, he finally succeeded in finishing himself off, taking his much-loved old dog and his much younger last wife with him. But I’m with the Nobel Prize-winning biologist Peter Medawar–no fan of pseudoscience–who declined to discuss astrology at cocktail parties because “I prefer to let sleeping unicorns lie.”

Well, then, homelessness: Where’s the mystery? He had been raised to expect a secular culture capable not only of assimilating but of embracing and promoting someone with his talents. It should have been possible, in Wittgenstein’s Vienna, to listen to Mozart or Schoenberg, read von Hofmannsthal or Herzl, go to a play by Schnitzler, look at Secessionists, consult Freud and consume a Sacher torte. It should have been possible, in Weimar Berlin, to listen to Hindemith and Weill, read Kafka and Rilke, look at Grosz and Dix, go to plays by Brecht and Piscator, and lollygag with Gropius in a Bauhaus. But they kept closing the borders, burning the books, banning the music and killing the thinkers, until there were no more homes, only camps. In this respect Koestler was every bit as “representative” of his generation as he wanted us to think, no matter how much Cesarani needs him to be some singular subspecies. Like most of the left in this century, he didn’t believe in God, and who can blame him? He tried Israel and didn’t like it: also hardly unique. He would settle in England, where he was at last as safe as Spinoza had been in Amsterdam. Isaiah Berlin once quoted Kant at him: “Out of the crooked timber of humanity no straight thing was ever made.” I’m sorry this “Casanova of Causes” was personally such a swine, the way I’m sorry Picasso was nasty, brutish and short. But I prefer to remember him as the Pest from Buda, the refugee stormbird, who, almost singlehandedly, got capital punishment abolished in his stepfatherland.