Ken Wilber is an American philosopher and writer known for his work in transpersonal psychology and integral theory. He has authored numerous books that explore the integration of science, philosophy, and spirituality, aiming to create a comprehensive framework for understanding human consciousness and development. Wilber's integral theory proposes that all knowledge can be organized into a coherent system, encompassing various perspectives and disciplines. His model includes concepts such as quadrants, levels of development, and lines of intelligence, which help to illustrate the complexity of human experience and promote a holistic approach to personal and societal growth.