He was, of course, a man better known for burning books than collecting them, yet by the time he died, at 56, Hitler owned an estimated 16,000 volumes. It was by any measure an impressive collection: first editions of the works of philosophers, historians, poets, playwrights and novelists. For him, the library represented a Pierian spring, that metaphorical source of knowledge and inspiration. He drew deeply there, quelling intellectual insecurities and nourishing fanatic ambitions. He read voraciously, at least one book per night, sometimes more, he claimed. “When one gives, one also has to take,” he once said. “I take what I need from books.”

He ranked Don Quixote, along with Robinson Crusoe, Uncle Tom’s Cabin and Gulliver’s Travels, among the great works of world literature. “Each of them is a grandiose idea unto itself,” he said. In Robinson Crusoe he perceived “the development of the entire history of mankind”. Don Quixote captured “ingeniously” the end of an era. He was especially impressed by Gustave Doré’s depictions of Cervantes’s delusion-plagued hero.

He also owned the collected works of William Shakespeare, published in German translation in 1925 by Georg Müller as part of a series intended to make great literature available to the general public. Volume six includes As You Like It, Twelfth Night, Hamlet and Troilus and Cressida. The entire set is bound in hand-tooled Moroccan leather, with a gold-embossed eagle, flanked by his initials, on the spine.

Hitler considered Shakespeare superior to Goethe and Schiller. While Shakespeare had fuelled his imagination on the protean forces of the emerging British empire, these two Teutonic playwright-poets squandered their talent on stories of midlife crises and sibling rivalries. Why was it, he wondered, the German Enlightenment produced Nathan the Wise, the story of the rabbi who reconciles Christians, Muslims and Jews, while it had been left to Shakespeare to give the world The Merchant of Venice and Shylock?

He appears to have imbibed his Hamlet. “To be or not to be” was a favourite phrase, as was “It is Hecuba to me”. He was especially fond of Julius Caesar. In a 1926 sketchbook he drew a detailed stage set for the first act, with sinister facades enclosing the forum where Caesar is cut down. “We will meet again at Philippi,” he threatened an opponent on more than one occasion, plagiarising the spectral warning to Brutus after Caesar’s murder. He was said to have reserved the Ides of March for momentous decisions.

He kept his Shakespearian volumes in the second-floor study of his Alpine retreat in southern Germany, along with a leather edition of another favourite author, the adventure novelist Karl May. “The first Karl May that I read was The Ride Across the Desert,” he recalled. “I was overwhelmed. I threw myself into him immediately, which resulted in a noticeable decline in my grades.” Later in life, he was said to have sought solace in Karl May the way others did in the Bible.

He was versed in the Holy Scriptures and owned a particularly handsome tome with “Worte Christi” (Words of Christ) embossed in gold on a cream-coloured calfskin cover that even today remains as smooth as silk. He also owned a German translation of Henry Ford’s anti-semitic tract The International Jew: The World’s Foremost Problem and a 1931 handbook on poison gas, with a chapter detailing the qualities and effects of prussic acid, the homicidal asphyxiant marketed commercially as Zyklon B. On his bedstand, he kept a well-thumbed copy of Wilhelm Busch’s mischievous cartoon duo Max and Moritz.

Walter Benjamin [the German-Jewish scholar who died in 1940 while fleeing the Nazi invasion of France] once said you could tell a lot about a man by the books he keeps. He proposed that a private library serves as a permanent and credible witness to the collector’s character, leading him to the philosophic conceit that we collect books in the belief we are preserving them, when in fact the books preserve their collector.

For the past half-century, the remnants of Hitler’s library have occupied shelf space in climatised obscurity in the Rare Book Division of the Library of Congress. The 1,200 surviving volumes that once graced Hitler’s bookcases in his three elegantly appointed libraries — wood panelling, thick carpets, brass lamps, overstuffed armchairs — at private residences in Munich, Berlin and the Obersalzberg, near Berchtesgaden, now stand in densely packed rows on steel shelves in an unadorned, dimly lit storage area of the Thomas Jefferson Building in downtown Washington, just across the street from the United States Supreme Court.

The sinews of emotional logic that once ran through this collection — Hitler shuffled his books ceaselessly and insisted on reshelving them himself — have been severed. A copy of his family genealogy is sandwiched between a bound collection of newspaper articles titled Sunday Meditations and a folio of political cartoons from the 1920s. A handsomely bound facsimile edition of letters by Frederick the Great, specially designed for Hitler’s 50th birthday, lies on a shelf for oversized books beneath a similarly huge presentation volume on the city of Hamburg and an illustrated history of the German navy in the first world war. His copy of the writings of the Prussian general Carl von Clausewitz, who famously declared that war was politics by other means, shares shelf space with a French vegetarian cookbook inscribed to “Monsieur Hitler végétarien”.

When I first surveyed Hitler’s surviving books in the spring of 2001, I discovered fewer than half the volumes had been catalogued, and only 200 of those were searchable in the Library of Congress’s online catalogue. Most were listed on ageing index cards and still bore the idiosyncratic numbering system assigned in the 1950s.

At Brown University, in Providence, Rhode Island, I found another 80 Hitler books in a similar state of benign neglect. Taken from his Berlin bunker in the spring of 1945 by Albert Aronson, one of the first Americans to enter Berlin after Germany’s defeat, they were donated to Brown by Aronson’s nephew in the late 1970s. Among the books at Brown, I found a copy of Mein Kampf with Hitler’s ex-libris book plate, an analysis of Wagner’s Parsifal published in 1913, a history of the swastika from 1921, and half a dozen or so spiritual and occult volumes acquired in Munich in the early 1920s, including an account of supernatural occurrences, The Dead Are Alive!, and a monograph on Nostradamus. I discovered additional Hitler books in public and private archives across America and Europe.

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