That's become a worldwide movement: https://en.wikipedia.org/wiki/BookCrossing
I got the idea from having found a book in my youth. I wasn't sure if the book had been left or lost, but it was a good book and the finding of the book led me to enjoying science fiction.
I figured I'd try to make it more meaningful than that and left books that had influenced me. However, I got only one reply. I should do it again but make them gift certificates for the local bookstore. Then they can read what they want.