Something good dealing w/ Mindfulness

So I've always been somewhat intrigued by the therapy practice of mindfulness but I would like to learn some more about it and maybe start practicing it myself. The only thing is, I was hoping someone could suggest me a book on the subject that really grips the reader. For some reason I've always struggled a lot more with non-fiction works but can fly through a lot of fiction, maybe because reading is a huge release for me and something I do to relax. But I'm open to all suggestions! Thanks in advance.