QUESTION: WHO CAN CLIMB A LADDER faster than a fire fighter? Answer: an immigrant.

Most Germans talking about their country's biggest foreign community would not get the joke. Their image of a Turk is the man who drives a battered Opel and owns the kabob shop downtown, or the woman who sells goat cheese and pine nuts at the corner store. In the bigger towns the Turk may be known as a textile salesman, or the person behind the counter at the travel agency. But while Germans haven't been watching, a large number of the 1.9 million Turks who live among them--more than a quarter of the country's foreign residents--have climbed up to middle class.

After only a few decades of adaptation--and plenty of harassment along the way--many Turks have gone from small beginnings to bigger things. Much bigger. Today some 37,000 Turks run their own businesses, many of which have earnings in the multimillions. Turkish enterprises produce more than $21 billion annually and employ 150,000 people, 15% of them Germans. Apart from providing a growing market for consumer goods, Turkish residents make investments of $1.9 billion a year. Says Andreas Goldberg, executive secretary of the Center for Turkish Studies in Essen: "The people who once ranked at the bottom of our social scale are now managers and investors moving millions."

Apart from food and retail businesses, Turks have gone into construction, printing, banking and tourism. In North Rhine-Westphalia, where migrant labor once filled the steel foundries and mines, many second-generation Turks have become lawyers, software experts, graphic designers. Turkish students--15,000 at German universities--are studying business management, economics, medicine and law.

Aydin Yardimci is one of the flood of Turks who helped to fill Germany's need for Gastarbeiter, or guest workers, a euphemism for cheap labor in the steel, auto and mining industries. Germany and Turkey signed an agreement governing the migration of Gastarbeiter in 1961, and in 1970 Yardimci, then 25, arrived to improve his skills as a mechanic. He spent five years with Cologne enginemaker Klockner-Humboldt-Deutz. When the time came to consider returning home, a relative, another Gastarbeiter, gave Yardimci $7,000 and said, "There's money to be made here." Today, at 51, Yardimci is a German citizen who is owner or part owner of businesses with total annual sales of $93 million.

His success sprang from that quality intrinsic to migration: foresight. When he decided to stay on, Yardimci forgot about engines and turned to meat. Turks love lamb, and more and more Turks were arriving. So Yardimci went to England and Scotland to acquire expertise and connections in the lamb business. Now his Cologne-based firm, Aydin Fleisch, is the biggest lamb wholesaler in Europe.

Yardimci also has interests in a bottling plant in Aachen and a plastics maker in Istanbul. He hasn't had a vacation in eight years, but he and his Turkish wife, Guner, have educated their three children in Germany, England and Turkey. Apart from doing business, Yardimci lobbies Bonn to begin permitting dual German-Turkish citizenship.

Recep Keskin took the academic elevator. A scholarship carried him from the central Anatolian village of Dervilsi to the University of Munster, where he earned an engineering degree. In 1989 the family-owned firm Schaumburg & Sieper, which has built tunnels, rail bridges and roads in Germany for a century, was looking for an engineer to head a new concrete-products subsidiary. Keskin got the managing director's job, plus part ownership of the new business. "My only capital was my know-how, my brains and my commitment," says Keskin, 46.

Last year Keskin opened a concrete plant in Gommern. In April he was given the Honorary Citizen of the Ruhr award for "exemplary management of a traditional German firm." Unlike Yardimci, he has not taken citizenship. "I'm a European, but a Turk," he says. In a gesture to his humble past, Keskin is providing financial support to an elementary school in Dervilsi.

The guest-worker agreement ended in 1973 with the post-oil crisis recession. Of those Turks who stayed, surveys show, 80% don't intend to return to their native country. Says Selva Ayar, 33, who owns an upmarket hairdressing salon in Dortmund: "I once thought of opening up in Turkey, but I couldn't deal with the inflation." Other Turkish women are also going into commerce. In Gladbeck, 25-year-old nurses Huriye Aydin and Huyla Yol have set up a service for the aged and bedridden. "I'm the only girl in the family, and the first to be self-employed," says Aydin, whose father was a Ruhr miner.

What does German business make of the tyro Turks? Heinrich Liese, of the Association of German Chambers of Industry and Commerce, says they create jobs, for Germans as well as fellow Turks. "But they are not only an economic asset," says Liese. "They convey an image of Turks as more than just kabob vendors. Every contact breaks down prejudices and stereotypes."

--Reported by Rhea Schoenthal/Bonn