Ken Wilber is the author of 19 books on psychology, philosophy, anthropology, religion, evolution, and enlightenment. He has transformed transpersonal psychology and established an "integral approach" that brings together science and Spirit. This excellent overview volume of his spiritual purview has been compiled and edited by Mark Palmer, Sean Hargens, Vipassana Esbjorn, and Adam Leonard.
The paperback is organized into sections on The Witness, Memoirs, Spirit-in-Action, Immediate Awareness, Passionate Philosophy, Always Already, Being-in-the-World, One without a Second, and The Brilliant Clarity of Ever-Present Awareness. Wilber shares his many mystical insights, spiritual practices, and interpretations of the teachings of Eastern masters. Here are some brief quotations to give you an idea of the range and creativity of his thought:
"Evolution is best thought of as Spirit-in-Action, God-in-the-Making, where Spirit unfolds itself at every stage of development, thus manifesting more of itself, at every unfolding."
"So also, our social and esthetic values are always put in terms of opposites: success vs. failure, beautiful vs. ugly, strong vs. weak, intelligent vs. stupid. Even our highest abstractions rest on opposites. Logic, for instance, is concerned with the true vs. the false; epistemology, with appearance vs. reality; ontology, with being vs. nonbeing. Our world seems to be a massive collection of opposites. This fact is so commonplace as to hardly need mentioning, but the more one ponders it the more it is strikingly peculiar. For nature, it seems, knows nothing of this world of opposites in which people live."
"To have any meaning at all, philosophy must sizzle with passion, boil your brain, fry your eyeballs, or you're just not doing it right. And that applies to the other end of the spectrum of feelings as well. Real philosophy is as gentle as fog and as quiet as tears; it holds the world as if it were a delicate infant, raw and open and vulnerable. I sincerely hope that if I have brought anything to this field, it is a bit of passion."
"I have one major rule: everybody is right. More specifically, everybody including me has some important pieces of truth, and all of those pieces need to be honored, cherished, are included in a more gracious, spacious, and compassionate embrace."