Each field’s intellectual and behavioral standards, including its ethical standards, come to be embodied, over time, in each trainee through the process of professional education and clinical training. This chapter examines the social processes by which newcomers, initially outsiders, become part of a professional community. What we see is that the processes of learning and progressive mastery are relational, social, and interactive. Trainees and clinicians, in coming to master this professional milieu, are inescapably also coming to master the moral milieu—the ethical values, standards, and goals—embedded in clinical health care. They become “embedded practitioners whose standards of judgment, canons of evidence, or normative measures are extensions of the community itself.”