This small book is about how, if we are fortunate, we get smarter as we grow older. Smarter not in the sense that our IQ score rises, but smarter in a much more important sense. This book is about the growth of human understanding, a kind of understanding that enables us to see both ourselves and others more clearly and, in the process, leads us to feel more deeply. Its focus is a remarkable new theory of the development of the self by Harvard psychologist...