Book excerpt: Spirituality.The search for happiness --Religion, East and West --Mindfulness --The truth of suffering --Enlightenment --The mystery of consciousness.The mind divided --Structure and function --Are our minds already split? --Conscious and unconscious processing in the brain --Consciousness is what matters --The riddle of the self.What are we calling "I"? --Consciousness without self --Lost in thought --The challenge of studying the self --Penetrating the illusion --Meditation.Gradual versus sudden realization --Dzogchen: taking the goal as the path --Having no head --The paradox of acceptance --Gurus, death, drugs, and other puzzles.Mind on the brink of death --The spiritual uses of pharmacology.