I used to leave them in cafes, but you might have to lurk & watch to make sure the staff don't throw them out.
I prefer to speak to the cafe staff first and ask if it's okay to leave a book and check they won't throw it out. I have never had my request refused, although one place said only two books at most. I've had several staff catch the books themselves, although most don't bother to log them. I even had one keen waitress want all the books, telling me she loved reading and promising she would log them. However, as I like to spread the books I only gave her a couple, which was as well, as she never (surprise, surprise) logged them.