Yet Trevor-Roper was a standout in his studies. He grew bored with the scholastic emphasis on the classics as obscurantist philological puzzles rather than treating the corpus of the ancient world as literature. He ended up focusing on modern history instead. All his life he inveighed against dry, tedious and provincial British pedants who lacked a broader understanding of European philosophical traditions. Oxford, he said, was a “dreary company of old men, haters of learning & intellectual activity.” Perhaps he was again echoing Gibbon, who wrote in his autobiographythat at Magdalen College the “example of the senior fellows could not inspire the under-graduates with a liberal spirit or studious emulation; and I cannot describe, as I never knew, the discipline of college.”

Trevor-Roper landed a Merton Fellowship at Oxford, noting with characteristic asperity about his examiners, “I hope I impressed them more than they did me.” Trevor-Roper did not spare his friends either. Maurice Bowra was humiliated to receive a postcard from his former student that pointed to an error in his Oxford Book of Greek Verse in Translation—he had mistaken a dirge for an epithalamium. “It was mortifying to have such a howler pointed out by one of his protégés,” says Sisman, “a man who wasn’t even a classicist—all the more so to have it exposed to casual scrutiny on a postcard. Bowra . . . nursed his resentment for years.”

Yet again and again, the fusillades he directed against his colleagues and peers—whether it was Lawrence Stone, Arnold J. Toynbee or A. J. P. Taylor—were on target. Not even Taylor, who surpassed Trevor-Roper by far in sheer output, could come close to matching his sweeping intellectual range or his penetrating judgments across the centuries, from ancient Greece to Tudor England to Nazi Germany. There is little that Trevor-Roper did not seem to know, and what he didn’t probably was not worth knowing.

FOR ALL his academic proficiency, it was World War II that made him. A visit in 1935 to Freiburg, Germany, where he witnessed local Nazis bellowing in the town square about reuniting the Fatherland, left an indelible impression and would prompt him to condemn Neville Chamberlain’s appeasement policy. In fact, he was one of the few Englishmen in the 1930s to have read Mein Kampf. Trevor-Roper did not dismiss it simply as the rantings of a lunatic. Quite the contrary. All his life he was convinced that Nazi ideology had to be taken seriously; he went on to argue that Hitler couldn’t simply be dismissed as an intellectual nonentity—a stance which later brought him into direct conflict with A. J. P. Taylor, who believed, or professed to believe, that Hitler was little different from any other German statesman and had no coherent plan but, rather, stumbled into World War II. (Taylor, however, toward the end of his life, wrote, “When I read one of Trevor-Roper’s essays, tears of envy stand in my eyes.” The sentiment was a particularly handsome one given that Trevor-Roper, at the age of forty-three, nabbed the Regius Professorship that Taylor—who was deeply wounded by his mentor Lewis Namier’s refusal to endorse him for the post—believed would be his.)

Trevor-Roper was appointed a second lieutenant with the Life Guards in 1939, but it was as a member of the intelligence service that he made a significant contribution. His historical training and knowledge of German allowed him to play a vital role in deciphering the codes of the German Abwehr. But he consistently chafed at the bureaucratic restraints he encountered, particularly the strictures of his hidebound superiors. He regarded counterintelligence head Major Felix Cowgill as a “purblind, disastrous, megalomaniac.” Were his superiors, he speculated, perhaps best described as “a colony of coots in an unventilated backwater of bureaucracy”? The contempt was reciprocated, to the point that his enemies almost succeeded in getting him charged with treason after he visited Ireland, which maintained neutrality during the war.

It was his early classics studies all over again: what Trevor-Roper admired was style and flair, the bold insight, not the tedious accumulation of detail for its own sake. While battling the Colonel Blimps in the bureaucracy, he sought out elder mentors. One such was the American expatriate Logan Pearsall Smith who was living in London and had been friends with Henry James, Walt Whitman, Edmund Gosse and James Whistler. To Trevor-Roper, Smith referred to himself as “your virginal octogenarian boyfriend.” Trevor-Roper, in turn, resisted Smith’s attempts to probe at his emotional inner life, such as it was. He even left Smith’s eightieth birthday party early because he became so annoyed by the relentless questioning. But Smith, who, Sisman writes, “was as much concerned with style as with scholarship,” made a deep impact on Trevor-Roper. And it was during this period that he began to polish the Gibbonian put-down, where clause after clause rolled on to form at once the most elevated and malicious sentiments possible—the Gibbon who had remarked in his Vindication that one of his clerical detractors, Henry Edwards Davis, might settle a point by consulting his library “any afternoon when I am not at home,” and who could famously observe of the younger emperor Gordian that

twenty-two acknowledged concubines, and a library of sixty-two thousand volumes, attested the variety of his inclinations; and from the productions which he left behind him, it appears that the former as well as the latter were designed for use rather than for ostentation.

Trevor-Roper wrought this style to perfection in his best seller The Last Days of Hitler. It was a piece of sleuthing that had been assigned to him by the secret services. Trevor-Roper’s friend Dick White, a brigadier commanding the counterintelligence bureau (later the head of MI5 and MI6), hit upon the idea of the inquiry and encouraged Trevor-Roper to carry it out beginning in September 1945. The idea was to dispel Stalin’s propaganda efforts to suggest that Hitler had escaped and was in hiding (in fact, the Russians had dug up his body in May 1945, and legend has it that Stalin used Hitler’s skull as an ashtray). Trevor-Roper displayed real initiative: it was a onetime opportunity to make history himself. He interviewed numerous Nazi bigwigs and tracked down Hitler’s last will and testament. He formed the fullest picture of Hitler’s final days, demonstrating beyond doubt that the Nazi leader had expired by his own hand in April 1945 and that his and Eva Braun’s corpses were doused with gasoline by his lackeys and set on fire. The skill with which Trevor-Roper fashioned his intelligence report bears comparison with the greatest historians:

In the absolutism, the opulence, and the degeneracy of the middle Roman Empire we can perhaps find the best parallel to the high noonday of the Nazi Reich. There, in the severe pages of Gibbon, we read of characters apparently wielding gigantic authority who, on closer examination, are found to be the pliant creatures of concubines and catamites, of eunuchs and freedmen; and here too we see the élite of the Thousand-Year Reich a set of flatulent clowns swayed by purely random influences.

Trevor-Roper’s most basic insight was that, for all its pretensions to totalitarian control, the Nazi system was, in essence, an inefficient and chaotic court system that consisted of rival paladins each seeking Hitler’s blessing.

It is surely significant, however, that Trevor-Roper had not alighted upon the topic of his own accord. The criticism for the rest of his life would be that he never produced anything that matched it. Perhaps Trevor-Roper stumbled into his work as a historian more than he, or anyone else, really cared to admit. What’s more, the Nazi era turned into a lucrative gig for Trevor-Roper; as Sisman underscores, he was repeatedly called upon over the decades to attest to the reliability and provenance of Nazi documents, a task he was prepared to undertake as long as it was accompanied by an imposing fee. The Last Days alone paid for his Bentley.

IMMUNE TO fashionable trends, Trevor-Roper condemned Marxism but refused to embrace Cold War orthodoxies. Though he lurched from one project to the next in the 1950s, signing book contracts only to repudiate them, his lengthy essays left a trail of victims behind. “I have decided to liquidate Stone,” he announced. Lawrence Stone himself later called it a “guerrilla attack.” Stone had drawn on documents about Elizabethan aristocratic debt that Trevor-Roper had unearthed in the Public Records Office and shown him. In essence, he had beaten Trevor-Roper to the publication punch. But his haste had led to some errors. Moreover, Trevor-Roper bridled at Stone’s thesis in “The Anatomy of the Elizabethan Aristocracy,” which depicted the royals as reckless spendthrifts. Not so, Trevor-Roper rejoined. Aristocratic fortunes were just fine during the Elizabethan era, thank you very much. Stone’s adjurations about the perils of debt, by contrast, formed a “puritanical message, so much in tune with the times and so antipathetical to Hugh’s cavalier instincts,” writes Sisman. Too true. Trevor-Roper was growing impatient with the procrustean Marxist theory of class struggle. His reply in the Economic History Review, “The Elizabethan Aristocracy: An Anatomy Anatomised,” was called “one of the most vitriolic attacks ever made by one historian on another.” He also went on to pillory the venerable economic historian R. H. Tawney, dismissing the notion that there had been a Marxist “bourgeois revolution,” led by a rising capitalist class in the seventeenth century.