The open bookcases of Offener Bücherschrank can be found at three spots in Vienna (see the website for other locations!). The concept: go there, have a look, take what you think you need to read, and enjoy / bring it back / take more back than you got in the first place.
Why do I like this? Because books are not made to stand on the same shelf for their whole “lifetime”. The way I see it, share what you think is great! And even if you do not like or understand a book, maybe someone else will – why not give it away?!
Since the contents change often, you will only see how many books you find in English, Turkish, Chinese, Arabic, or Esperanto when you get there. In case you are looking for a specific book, better ask your trusted search engine for a nearby “Buchhandlung”.
Everyone else: experience the unknown ~ Happy reading!
PS: More places for free books are popping up around the city and even in Austria.