The spy who came in from the desert heat in Ken Follett's The Key to Rebecca lived no more dangerously than John Eppler, the German secret agent on whose escapades the novel is roughly based. Like Achmed/Alex Wolff, Eppler crossed the Sahara—but in a Ford. Near the Egyptian border he abandoned the car and the British uniform he'd worn for safety and walked to a British outpost. Posing as a stranded motorist, Eppler was given a Scotch, lunch and a ride to the train station. No curious Captain Newman dogged him, and Eppler reached Cairo safely in May 1942.

Now 66 and a millionaire businessman living outside Paris, Eppler says, "I was an adventurer in those days. I still take risks, but with money, not with my life."

The son of a wealthy Egyptian father and German mother, Eppler had spent two years in India and the Middle East spying for the German army before returning to Cairo. He was given $5 million to maintain his cover as a wealthy playboy. "I lived better than 007," he says. He wined and dined Cairo society, including top British officers.

His accomplice was a voluptuous belly dancer named Hekmat Fahmy. "There's a love story in all this," Eppler chuckles. "She would never have worked for me if she hadn't fallen in love with me." Fahmy would ply British officers with liquor, invite them to her houseboat on the Nile and then take them to bed. Meanwhile Eppler went through their papers and wallets in another room.

The intelligence he gathered was sent to Rommel's staff in North Africa by a telegraph hidden in the bow of Eppler's houseboat. It was docked nearby, alongside one used by the chief of British intelligence. "He was a gentleman," Eppler recalls. "We golfed together and he even sent over his driver to help put up the radio antenna on my boat." The key to the code that Eppler used was found in the English version of Daphne du Maurier's novel Rebecca.

Seven months after Eppler's desert crossing, the British discovered a copy of Rebecca on a captured German telegraph operator and subsequently broke the spy ring. Surrounded by British troops on his houseboat, Eppler initially held them off by throwing out socks that rolled up to look like a hand grenade. He hoped to slip into the Nile and escape, but the effort failed. He was seized, jailed and, he says, tortured. "In the end, I talked like the others," Eppler admits. "But I took so long the news was old when they got it. Even Jesus talked on the cross." He remembers the British, by and large, as gentlemen. In fact, one of his captors became a good friend after the war.

The belly dancer was arrested too. "When they asked her to identify me," Eppler reports, "she spit in my eye and said: 'I don't know this dirty Nazi.' " Eppler repaid her loyalty by buying her a Cairo nightclub, and they remain friends.

Sentenced to death by the British, Eppler was spared because his influential family persuaded Egyptian King Farouk to intervene. After two years in jail near Cairo, Eppler was given occasional furloughs for good behavior. During these he plotted with Anwar Sadat and Gamal Abdel Nasser to drive the British from their homeland. "Sadat was a good boy," Eppler recalls, "but he never had any cigarettes. He was always taking mine." Nasser and Sadat, of course, eventually came to power. "If I had continued in politics, I'd be dead," Eppler believes. "I wanted to live."

In 1946 he was released from prison and immediately contacted by the KGB. He declined to spy for the Soviets. "I saved my head once," he says. "I couldn't do it twice." He had been attracted to espionage as a boy after his father pointed out Lawrence of Arabia in Egypt. "That Englishman made me dream," explains Eppler. As a teenager, traveling the desert on camel with his uncles and living with the Bedouins ("Every son had to do that"), Eppler decided, "I had more right to that life than Lawrence. I was an Arab." So in 1937, at 23, he joined the German secret service. "I did it for fun and adventure and Egypt," he says. On a foray into Afghanistan, he disguised himself as a rug merchant: "I bought three mules, didn't wash, ate garlic and grew a mustache," he recalls.

Imprisonment changed Eppler's attitude toward espionage. "In jail I learned a lot about life," he says. "I developed a philosophy. Before that I wasn't a man." After rebuffing the KGB, Eppler sold cigarettes on the black market to finance his engineering studies near Hanover, Germany. He went into construction and became wealthy building factories around the globe. One of them is in Ohio; it produces material for blast furnaces. These days Eppler travels from Budapest to Amman to Helsinki to Rio supervising projects. He prides himself on his fluent command of German, English, French, Italian and Swahili, as well as five dialects of Arabic. "Money can be lost overnight," he says, "but no one can take languages from you."

Since 1957 Eppler has been a resident of France. He lives in a modest apartment near Versailles with Laure Reimbold, 32, an engineer who will soon become his fifth wife (Earlier spouses included a Danish ballet dancer and a Hungarian countess).

Looking back, the ebullient Eppler has no regrets—even that his nonaction version of the Cairo adventure, published in Europe six years ago as Operation Condor, never became a best-seller. "I don't like the word 'spy,' " Eppler says. "It gives the illusion that you are a cross between Tarzan and a hunting dog. I'm neither. A spy is a man like all others."