I first noticed these book shelves on some of the streets here in Frankfurt a few years back when a friend I was with stopped at one whilst we were walking past. I had no idea what they were but she explained that they are called “Öffentliche Bücherschränke” and people can place books in and take books out free of charge.
See a book you like, simply take it, finished with a book and want to give it away, simply place it into one of these many book shelves which are open 24/7
Sometimes they even have children’s books on the bottom shelf.
D was very happy with this find in the one at Merianplatz a few months back.
We came across a Berlin travel guide once at the one in Dornbusch, which we have since used for our Berlin trip & returned it for someone else to make use of.
Although they are mostly in German I have seen a couple of English ones & its always worth a look if you are passing as you never know what you might find!
Click here to see a list of all the locations of Öffentliche Bücherschränke in Hessen.