The development of so many different occupations on a professional basis or aspiring professional basis, has been the main way of institutionalizing expertise in industrialized countries. In the agency model, the client should have most of the authority and responsibility for decisions, with the professional an expert acting at the direction of the client - in effect, as an employee. The chapter focuses on the question of when are professionals of one kind or another the most appropriate agents to respond to an ethically challenging situation. Depending on the size and nature of the ethically challenging situation, a professional responding agent may appropriately be an individual or a collectivity. The situation becomes more complicated when a collectivity contains people from a number of professional occupations. While ethicists are gaining employment in various fields, the field of bioethics in the United States has demonstrated the strongest development.