Robert Kegan is a trained psychologist and Professor of Adult Learning and Professional Development at Harvard University. In 1982 he presented his advanced stage model of human development in his book The Evolving Self, and in 1994 he elaborated the model further in another important book, In Over Our Heads: The Mental Demands of Modern Life. Later, leadership, change, and professional learning and training have become the focus of his work. His interest in the transformations that lead from one developmental stage to the next has led him to take up Jack Mezirow’s concept of “transformative learning” (see Mezirow’s chapter later in this book), as can be seen in the following chapter, which is a slightly abridged version of Kegan’s chapter in Jack Mezirow et al. (2000), Learning as Transformation: Critical Perspectives on a Theory in Progress.