That is what those book corners are for. In Germany a lot of old public phone cells have been repurposed for that. Just don't overload them and also consider taking some books that interest you. Somehow it regulates and I guess someone also throws away stuff from time to time. I actually would not consider many of those listed in the OP 'libraries' because I rarely see books returning. There are more books exchanges. I liked the idea of bookcrossing.com that gives more value to the books (I never got any ping back though). There are also book resellers (some buy per weight, some let you estimate price by ISBN scanning before sending them)