By Paula Chin
October 26, 1992 12:00 PM

SITTING IN THE ELEGANTLY SUBDUED OFFICES of his menswear firm high above Madison Avenue, Manhattan designer John Weitz is explaining how he, of all people, could be an authority on Nazi Germany. “Find me another fashion designer who was born in Germany, served in the OSS and knows the Nazi Party to the point where many people, including the President of Germany, consult him about it,” he says. Then, smiling, he pulls back from the brink of pomposity. “Find me a fashion designer who has those qualifications…and I’ll show you a lousy fashion designer!”

Weitz, 69, is known not only for his clothes but also for his ads—those curious, photoless posters with nothing but teasing snippets of conversation emblazoned on the backs of buses in New York City. His new book, Hitler’s Diplomat—a dispassionate, detailed biography of Joachim von Ribbentrop, the onetime champagne salesman who became Adolf Hitler’s foreign minister—may bring even more cachet to the Weitz name. The New York Times called it a “thorough, engaging” work of “designer craftsmanship” that guides readers through Ribbentrop’s life, up to his execution by hanging in 1946 for complicity in the Third Reich’s reign of terror. The Times of London praised Weitz’s “keen, discerning understanding of most of the cast of clowns, rogues and psychopaths who inhabit his elegantly written pages.”

“Who but a fashion designer would understand a social climber?” asks Weitz. In his view, Ribbentrop was the ultimate go-getter, an aristocrat who became enamored of Hitler. Having no ideology or scruples, he used everything and everyone to ingratiate himself with the Führer, says Weitz, simply because “he wanted to be terribly important in the world. Eventually, that’s what he got.”

Diplomat isn’t merely the portrait of an opportunist. Weitz, who was born into a wealthy Jewish family that fled Germany in 1938, was pursuing a longtime fascination with his fatherland and how it came to be seduced by a madman. “The important thing is the 70 million, not the one twerp,” he says. “I wanted to write about the Nazis through the eyes of somebody I might have met at a cocktail party, so I could say, ‘Don’t give me the party line. I want the country club talk.’ ”

Weitz managed to evoke Ribbentrop’s world thanks to his own privileged background and several years of research. He interviewed scores of eyewitnesses, including Ribbentrop’s 80-year-old former secretary, who knew Germany before and during Nazism. Weitz’s own social connections also helped. “I have sat in rooms for the last 40 years talking to people who sat at dinner tables with Hitler,” he says. Other connections were more unsettling. While looking through Ribbentrop’s family albums at the National Archives in Washington, “I felt slightly embarrassed because the albums look exactly like my family’s,” he says. “[The Ribbentrops] went to the same resorts, played on the same tennis courts, wore the same clothes.”

Born in Berlin, Weitz was the only child of a prominent textiles manufacturer, Robert Weitz, and his fashionable wife, Hedy. At 9, he was sent to London’s prestigious St. Paul’s School where, even in regimented uniforms, he cut a stylish figure. One teacher told Weitz’s classmate, the art critic John Russell, that Weitz’s grades might improve if he paid less attention to the cut of his collars and more to French declensions. Meanwhile his parents were alarmed by the virulent anti-Semitism at home, and by the time Weitz was 15, they had decided to flee to America. After finishing school in London—where, because German-born, Weitz was classified an enemy alien—he spent a year in Shanghai waiting for a U.S. visa before he joined his parents in New York City.

In 1943 his fluency in German landed him a job with the Voice of America. Weitz joined the Army, then became a U.S. citizen after he was assigned to the Office of Strategic Services, the forerunner of the CIA. Working as an undercover espionage agent, he infiltrated enemy lines in France and worked with the German Resistance, including the officers who plotted the unsuccessful assassination attempt on Hitler in 1944. After leaving the OSS, Weitz was among the troops who liberated the concentration camp at Dachau. “To me, the Holocaust means that grim, horrible day,” he says. “I can never forget.”

After the war, Weitz began designing ready-to-wear women’s clothes in New York City. He formed John Weitz Designs in 1954, and after LIFE magazine highlighted him in an article, his career took off. “I never planned on being a great couturier,” says Weitz, who switched to menswear in 1964. “To me fashion is not an art but a craft.” And one he mastered extremely profitably; his licensing empire, which also splashes his name on colognes, luggage and cigars, pulled in $250 million last year. For a while the striking, 6’2″ designer posed for his own ads, but it was the quirky, quotes-only ones, which he created with the ad agency C.J. Herrick Associates, that really created a buzz. “The idea is to amuse without annoying and make for a little adult entertainment,” he says. “My favorite is the one that reads, ‘Cute.’ ‘What? The one wearing the John Weitz tie?’ ‘No, the one standing next to him.’ ”

Weitz’s pursuits are as dashing as his looks. His favorite is race-car driving, which he calls “the affliction of all European boys of my generation.” From 1954 to 1960 he was an international amateur race-car driver who competed in Sebring, Fla., and the Bahamas Grand Prix circuits. “I drove Morgans, Bristols. It was a fashionable, poloesque sport that’s now gone,” he says. Though he has sold off his vintage-car collection—they dripped too much oil, he says—he still keeps a Jaguar and a Ferrari Testarossa, which is capable of hitting 180 m.p.h. “He doesn’t smoke or drink. He has to have some vice,” says former actress Susan Kohner, now 55, who retired after marrying Weitz in 1964, shortly after his second divorce, from fashion editor Eve Orton. The couple have two sons, Paul, 26, a playwright, and Chris, 22, a journalist who graduated from Cambridge. (Weitz also has two children, Karen, 43, and Robert, 41, from his first marriage, in 1943, to Philadelphian Sally Blauner.)

The Weitzes divide their time between Manhattan and Westhampton Beach, on Long Island, where he boats and she gardens. Weitz began to fit writing into his busy schedule 30 years ago after John Steinbeck, who was living in nearby Sag Harbor, told him, “You had a decent education, you’ve no right not to write.” Weitz was receptive. “I asked him how to do it, and he said he’d tell me the next morning,” says the designer. “He arrived that day with a big yellow lined pad and said, ‘This is how you write.’ ” Weitz soon began his first novel, The Value of Nothing—about a New Yorker from an unlikely background who becomes a fashion designer—which hit the 1970 best-seller lists. A 1982 novel about the Third Reich called Friends in High Places became a cult favorite in Germany.

Weitz is already planning his second historical book, about the Gestapo. As usual the subject isn’t nearly as important to Weitz as the setting. Writing about Hitler’s Germany, Weitz says, is less an obsession than a duty. “If you are a witness to anything that needs to be set straight,” he explains, “then you must tell about it.”