By the early 1980s, Günther Wallraff had already earned a sterling reputation as one of the country's top investigative journalists. He tirelessly uncovered postwar Germany's darkest secrets, lifting the lid on the country's psychiatric hospitals, factories, tabloid newspapers and intelligence serves.
But Wallraff's most profound impact on German society was made when he adopted the identity of Turkish guest worker Ali Levent. Wallraff spent two years undercover, experiencing first-hand the difficulty of life in Germany's immigrant netherworlds.
Twenty years ago this week, he published "Ganz Unten" or "The Lowest of the Low", a book that would become the definitive work on Germany's immigrant workforce and resonate with readers around the world. Three million copies of the book were sold over the ensuing three years, prompting the nation to put a more human face on its Turkish community, and also confront the unacceptable conditions this workforce had been subjected to since its arrival in the 1950s.
A "shock to the system"
"I think the book was a shock to everyone's system," Wallraff said. "It was read by everyone, including sections of the public who would never normally go to bookstores. Back then, it was the best-selling book in Germany's post-war history, and it really spoke to everyone's conscience."
Germans began to take notice of their Turkish neighbors and the words and tone used to depict the plight of the immigrant workforce changed dramatically.
"People started talking about the modern slave trade, and became more sympathetic to the victims," said Wallraff. "There was a gradual clamp-down on the big earners, the human traffickers."
"I received thousand of letters from Turkish immigrants who said that their German neighbors and colleagues had started chatting to them for the first time," he said. "I believe the book relieved their sense of alienation here."
A standard work for a generation of Turks
"The Lowest of the Low" was translated in 30 languages, becoming standard reading in many countries, including Turkey.
"Günther Wallraff's book was a thunderbolt," said Turkish journalist Asim Gürsoy. ""It really highlighted the plight of Turkish immigrants. Until then, Germans had no idea what immigrants were up against. The book still hasn't been forgotten. It's a seminal work on immigrant issues that should be compulsory reading for young Turks and Germans."
For many young Turkish people living in Germany, it already is. Student Öznur Özcan says reading the book is instrumental in understanding how far Germany and its immigrants have come - and how far they still must go.
"If you think about whether the same problems still exist today … then you realize that some things haven't changed," he said. "But the problems aren't as acute as they were twenty years ago."
Germany's continuing integration problem
Wallraff might disagree. The dismantling of Germany's once-generous welfare state through the pressures of globalization threatens to force a whole new generation to join the "lowest of the low", he said. Turkish guest workers have now been replaced by Romanians, Poles, Russians, and the long-term unemployed from the former East Germany.
"Back then, the Turkish workers were getting paid 6 Deutschmarks ($4) an hour," he said. "Today, people are working for 2 euros ($2.50)."
He believes Germany still has a long way to go before it's dealt with questions of immigrant integration.
"Germany still has to rid itself of its prejudices," he said. "I feel the majority of German society is still unaware that immigration brings with it a number of advantages, that in fact it helps society survive. Even the conservatives have to acknowledge that society is condemned to die out because it's hostile to children and outsiders. It thinks it's better than everyone else, and for as long as that's the case, it will stagnate, it will remain in a steady decline."