COLOGNE, Germany — 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 €5,000 ($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.

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.