By Michael Bloch

Crown. 528 pp. $25

EVERYONE he encountered thought him a fool. Franz von Papen believed him "immensely industrious, but devoid of intelligence." Joseph Goebbels took pleasure in telling people that he had "married his money and bought his name." His own mother-in-law once lamented, "Of all my sons-in-law, the most foolish became the most prominent." He was universally considered to be a humorless, pompous bore.

So how could such an oafish nonentity of a man as Joachim von Ribbentrop survive as Hitler's foreign minister for six bloody years? More disturbing, how could a man so transparently stupid -- even to his own collaborators -- inflict such evil upon the world?

Michael Bloch, the author of this engaging biography, argues that Ribbentrop was not merely a stooge, that he was indeed Hitler's most reliable "yes-man," and that "he did possess a gift which endeared him enormously to Hitler: that of taking some half-formed idea of the Fuhrer and elaborating it, in the course of a discussion, into some grand vision. He was a music maker and dreamer of dreams." It must be a difficult assignment for a biographer to make a man of such derision -- the British press once dubbed him "Brickendrop" -- interesting at all. That is Bloch's achievement.

Make no mistake, Bloch is not a biographer seduced by his subject. This is a critical, even hostile portrait of a pathetic figure in the Nazi pantheon. But Bloch, previously the author of several books on the Duke of Windsor, argues that knowing this foolish man is important to an understanding of the Third Reich.

Given the immense literature on the Nazi period, it is curious that it has taken all these years for anyone to focus on Ribbentrop's role. (After his execution by hanging at Nuremberg, Ribbentrop's still-devoted wife published his prison scribblings under the title, The Ribbentrop Memoirs, but the book was less than half done.) Bloch's is actually the second biography, the first being John Weitz's Hitler's Diplomat, published just last year. Nine years in the making, Bloch's is clearly the more definitive treatment. He has delved deep into the relevant German, English and American archives -- though not the Soviet archives -- and produced a graceful narrative of Ribbentrop's life.

Ribbentrop was born in 1893, the second son of a Prussian artillery officer. His mother, an accomplished pianist, died of tuberculosis when he was only 8. Three years later, in 1905, his father married a 22-year-old woman from the von Prittwitz clan, a distinguished Prussian landowning dynasty. Bloch makes a convincing case that many of Ribbentrop's lifelong insecurities came from this adolescent awareness of class distinction.

Keenly aware of the "von" that prefixed his stepmother's maiden name, in 1925 Ribbentrop would literally buy himself the title by having a distant ennobled relation adopt him in return for his payment of a regular pension.

As a young man, Ribbentrop spent four years in Canada, where he might have happily remained had he resisted the urge to serve the Fatherland in 1914. During the war, he earned an Iron Cross and, significantly, made the acquaintance of one Franz von Papen.

Ambitious, but uneducated, Ribbentrop became first a smuggler and then a registered importer of spirits. He also proved himself an adept social climber, first with his clients and then by marrying Anna Henkell, the daughter of the manufacturer of Sekt, the German sparkling wine. Though there was money, they evidently married for love. She became the driving force behind his career, to the point that one of Ribbentrop's foreign ministry officials remembered her as "a true evil genius."

The Ribbentrops prospered throughout the Weimar years; he proved to be a good businessman, at one point winning the franchise to market Johnny Walker whiskey. In 1930, he also became an active but covert supporter of the Nazi party, and later that year met Hitler for the first time. His conversion apparently had nothing to do with politics (he did not even seem to be particularly antisemitic) and everything to do with opportunism. WITHOUT exaggerating his influence, Bloch shows Ribbentrop playing a key role as a middleman between Hitler on the one side and Chancellor Franz von Papen and Reich President Paul von Hindenburg on the other in brokering Hitler's rise to the chancellorship in 1933. It was Ribbentrop who provided a discreet venue for the crucial meetings at his Berlin-Dahlem villa. And when the negotiations broke down, it was Ribbentrop who got the parties talking again.

Of even greater historical interest, however, is Bloch's discussion of the Molotov-Ribbentrop Pact of August 1939. Was Ribbentrop -- who even then was the laughingstock of the Nazi government -- the man who started World War II? Bloch would like you tothink so. He reports Hitler hailing his foreign minister as a "second Bismarck" when Ribbentrop returned from Moscow. Ribbentrop had assured Hitler that the Nazi-Soviet pact gave his Fuhrer a free hand to wage his little war in Poland without fear that the Western powers would intervene. This was certainly illusory advice, but would it have made any difference if Ribbentrop had told Hitler the British would fight? Ultimately, Bloch says he can't answer this question because of the "impenetrability of Hitler's mind."

Instead, he concludes this critical chapter by quoting the memoirs of Hitler's personal photographer, Heninrich Hoffman, who intensely disliked Ribbentrop:

"Again and again, I had heard Ribbentrop, with a self-confidence out of all proportion to his knowledge and powers of judgment, assure Hitler that Britain . . . would never fight. It was above all the promptings of Ribbentrop at his elbow . . . which eventually brought the Fuhrer and his country to destruction."

There is enough here to intrigue, but one recoils from the rank whiff of revisionism in Hoffman's lament for his Fuhrer. Ribbentrop's stupidity can't excuse, and by itself doesn't explain, how Hitler led the German people, oh so willing, to total war. The notorious David Irving (a self-described "mild fascist") -- to whom Bloch curiously gives a nod in his acknowledgements -- has made a career arguing that if it had not been for the "clumsy and mindless brutality of Hitler's underlings," the Fuhrer and his Third Reich would have met a different fate. Fortunately, this is not Bloch's thesis. His Ribbentrop is an idiot who merely encouraged Hitler's demonic instincts. Kai Bird, the author of "The Chairman: John J. McCoy, The Making of the American Establishment," is writing a biography of William P. Bundy, McGeorge Bundy and their father, Harvey Bundy.