"Be here now", by Ram Dass (http://it.scribd.com/doc/6531720/Ram-Dassbe-Here-Now) is a great book about living in the now. I recommend it to anyone who wishes to teach oneself on how to stop thinking about the past and the future. Simply start enjoying the only truthful moment we really have, which is right now. Float in the moment of now and you will float with the universe.