Take a book, leave a book. In the birthplace of the printing press, public bookshelves are popping up across the nation on street corners, city squares and suburban supermarkets.
In these free-for-all libraries, people can grab whatever they want to read, and leave behind anything they want for others. There's no need to register, no due date, and you can take or give as many as you want.
"This project is aimed at everyone who likes to read without regard to age or education. It is open for everybody," Michael Aubermann, one of the organizers of the free book exchange in the city of Cologne, told The Associated Press.
The western city's latest public shelf, a euro5,000 ($6,883) steel bookcase with acrylic glass doors, was put up two weeks ago next to Bayenturm, one of the city's medieval towers. It is the fourth free shelf that Aubermann's group, the Cologne Citizen's Foundation, has placed outside; there are two more inside local Ikea outlets.
"We installed our other outdoor shelves last year and it's been working really well," said Aubermann, a 44-year-old who works in IT management.
The public book shelves, which are usually financed by donations and cared for by local volunteer groups, have popped up independently of each other in many cities across Germany including Berlin, Hannover and Bonn, and also in suburbs and villages.
Each shelf holds around 200 books and it takes about six weeks for a complete turnover, with all the old titles replaced by new ones, he said.
Vera Monka, a 46-year-old Cologne resident who works in catering and event management, said she takes advantage of the free books all the time.
"I have often left books here, but frankly, I have even more often taken books with me," she said, browsing through the latest new arrivals at the Bayenthal shelf.
"For me personally, this project is simply great, because I do not have much money left to spend on good literature."
Even commercial book stores and online book retailers seem to support the idea of free book exchanges.
"We see this project rather as a sales promotion than as competition," said Elmar Muether, the acting branch manager at Cologne's Mayersche Buchhandlung book store. "If books are present everywhere, it helps our business too."
Bettina Althaus, a spokeswoman for buch.de, a German online bookstore comparable to Amazon.com, also welcomed the movement.
"Public bookshelves are in no competition with the online book trade. On the contrary, we are happy about any kind of motivation to read," Althaus said.
So far, the Cologne book group has had few problems with vandalism or other kinds of abuse, though a used-book seller once scooped up every volume on a shelf to sell at a flea market. Another time the shelves kept getting stacked with material from a religious group.
"We made sure to get rid of that stuff as quickly as possible," Aubermann said. "Propaganda is the only kind of literature we do not allow here, whether it is right-wing, racist or proselytizing."
The book cases are like small treasure chests with an eclectic mix of anything from fiction to obscure self-help, travel guides or crime novels. During a recent visit, the bookshelf at Bayenturm was well equipped with hardcover classics including Erich Maria Remarque's All Quiet on the Western Front, Siegfried Lenz' The German Lesson and Gone with the Wind by Margaret Mitchell. There was also an APA paperback guide to New York State, science fiction, a book on witchcraft and various dog-eared crime novels.
At another bookshelf in the Bayenthal neighborhood, the lower shelves were reserved for children's literature only.
"It is important that we make it easy for everyone to overcome their inhibitions and participate in this 'reading culture on the street' from old readers to kids to immigrants," Aubermann said.
While most of the shelves have so far been put up in upscale neighborhoods, Aubermann and the 20 volunteers who help look after the project are planning to put up future shelves in poor neighborhoods, where residents often don't have as much access to literature.
Nobody really knows where the idea for the public shelves originally stems from. What's certain is it's a popular grass-roots movement that's catching on even abroad.
Just a few weeks ago, Aubermann said he was contacted by a Portuguese NGO that asked him for help with opening public book shelves in poor rural areas of Mozambique.