One of the most influential views of reflective function in the history of psychoanalysis, and clearly the most influential view of that subject in the current literature, is that of Fonagy and his collaborators (2002). Their work has reignited interest in reflection and reinvigorated its study. Since the beginnings of our field, self-reflection has lost a great deal of ground to relational effects in our theories of therapeutic action. That is as it should be, and Fonagy et al. would be the first to agree. In fact, perhaps their most significant theoretical contribution has been their detailed proposal that the development of mind, including reflective function, is itself thoroughly relational. Reflective function is a relational event, with relational roots. As a result of this work, reflection is no longer a dusty subject on the back of the shelf. It is now as fascinating as it was long ago, and it is back in the center of psychoanalytic interest. The work of Fonagy et al. has deeply affected my own work, a fact reflected in the frequent citations of mentalization theory in this book. Their description of the process of mentalization and their observations about how it develops are with me whenever I sit down with patients. I use their observations and their conceptions every single day.