If you are open to a spiritual journey, Eckhart Tolle's book A New Earth: Awakening to Your Life's Purpose has been noted as a powerful and transformational spiritual experience. It is the talk among over 5 million people around the world who have signed up to join Oprah's interactive classroom discussions led by Tolle & Winfrey (already 4 weeks into the 10 week program).
Tolle traces the root of human suffering to the 'ego'. He speaks of the critical transcendence of our ego-based state of consciousness as the key to personal happiness, and resolution to existing disharmony in the world. Like many philosophers and psychologists of previous centuries (Descartes, Freud etc...), Tolle describes how our attachment to the ego creates dysfunction and inevitable unhappiness. He encourages readers to awaken to a new state of consciousness and follow the path to a fulfilling existence.