Psychotherapy is a practice in search of a theory. Recent advances in relational neuroscience and attachment research now offer convincing avenues for understanding how the ‘talking cure’ helps clients recover. Drawing on Karl Friston’s Free Energy Principle and contemporary attachment theory this book shows how psychotherapy works. This pioneering text provides a deep theoretical explanation for how psychotherapy helps sufferers overcome trauma, redress relationship difficulties and ameliorate depression. Neuroscience validates the psychoanalytic principles of establishing a trusting therapeutic secure base; using ambiguity to bring pre-formed assumptions into view for revision; dream analysis, free association and playfulness in extending clients’ repertoire of narratives for meeting life’s vicissitudes; and re-starting the capacity to learn from experience. Holmes demonstrates how psychotherapy works at a neuroscientific level, making complex ideas vivid and comprehensible for a wide readership.