Only once every 10 to 15 years does a book emerge that is as innovative as this one. Martin Dornes describes it: "The new Fonagy book will be a new Daniel Stern!" Lotte Köhler emphasizes that this book represents a large-scale synthesis that addresses the dynamic interplay between psychoanalysis and attachment theory. It successfully bridges the two disciplines by re-examining the concept of attachment. It is no longer just about establishing attachment itself, but about equipping the child through secure relationships to develop an understanding of mental states in others and in themselves. The concept of mentalization thus becomes a central point for human functioning in a social context. Mentalization is understood as the ability to respond appropriately to another person's behavior.