A number of individuals have contributed to this work, directly and indirectly. Charles Laughlin's neurophenomenological perspective is a guiding influence throughout this book. I thank him for that and for his comments on specific chapters. Harry Hunt's work, particularly his book On the Nature of Consciousness, provided crucial insights incorporated here. I also thank Stanley Krippner for his encouragement of my work over the years and for his insightful perspectives. Thanks are also due to Marilynn Bubb for assistance with word processing and proofreading.