For each of us, our thoughts, beliefs, desires, expectations, and fantasies constitute our own sense of a unique identity. Here, Jungian and relational psychoanalyst Jean Knox argues that this experience of self-agency is always at the heart of psychological growth and development, and it follows a developmental trajectory that she examines in detail, from the realm of bodily action and reaction in the first few months of life, through the emergence of different levels of agency, to the mature expression of agency in language and metaphor.

Knox makes the case that the achievement of...