Our grasp of the scientific method has evolved, as have key disciplines of cognitive science, developmental psychology and neuroscience, not to mention crucial shifts in the practice of psychotherapy. However, aspects of our theories for the developing mind (our metapsychologies) have remained vague, less articulated. But this may be changing as well. Attachment Theory represents an important piece-not the only piece-in the theoretical puzzle that is the mind: encompassing affect, intentionality and agency, historically troublesome notions for scientific study. The presentation will cover: (1) ‘What Attachment is’ in 2011, and its growing cross-modality contribution to the practice of psychotherapy; (2) ‘What it is not’, identifying longstanding misconceptions, potential risks for misapplication, but also indicating legitimate criticisms and theoretical gaps requiring more study; and finally, (3) ‘Why it matters’, taking a more philosophical perspective, suggesting how Attachment Theory may contribute to a much, needed articulation of a ‘causal’, ‘evidential’ and ‘theoretically coherent’ case for longer-term psychotherapy (complimenting, if not challenging, other ‘evidence based’ models that may predispose treatment policy decisions toward more ‘short-term only’ approaches.