Check out Zen Mind, Beginner's Mind for a good book on practicing meditation. It's not religious, but basically a transcript of a Zen Master's talks on zen and the practice of meditation to his group of students. It's what I recommend to people who want to 'get' meditation.

http://www.amazon.com/Zen-Mind-Beginners-Shunryu-Suzuki/dp/1...

Not specifically related to meditation, but The Tao of Pooh is still the best book I know of that deals with the concepts behind this stuff. I re-read these books whenever I lose my way, which happens more often than I'd like to admit ;)

I'm currently reading The Instinct to Heal by David Servan-Schreiber [0]. It's not specifically about mindfulness, but so far I found it everything to be what I was looking for when I was looking for writings on these topics. On the internet I've seen a lot of essays pass by about mindfulness, but they're all a bit alike. This book is interesting to me because it gives info about methods I didn't know about, and provides scientific data and references to base its claims. [0] https://www.goodreads.com/book/show/153401.The_Instinct_to_H...

Not about mindfulness, but I highly recommend this book: http://www.amazon.com/Brain-That-Changes-Itself-Frontiers/dp...