Whether it's at a book exchange box or on a train or bus, leave a book you have enjoyed for someone else to enjoy. Add an inscription maybe in the front to explain what the book is for (so people don't try to return it to you somehow).
East Village, London
To promote literacy and the love of reading by building free book exchanges worldwide and to build a sense of community as we share skills, creativity and wisdom across generations.
Or you could join Book Crossing where you can register your book, release it into the wild and as other people resister as they find it and release it again, you can follow the progress of your book who-knows-where...