The Power of Now by Eckhart Tolle is truly a spiritual guide with the potential to be life-changing. Tolle introduces the book by describing his spiritual awakening and its immediate consequences. Written in a question/answer format, his book is very readable, containing both practical/useable concepts and profound insights. He acknowledges reading A Course In Miracles, and his writings are compatible with it. I found The Power of Now inspiring, challenging, and enlightening. I also recommend his sequel A New Earth published in 2005.