Social work has been defined as being "concerned with the interactions between people and their social environment which affect the ability of people to accomplish life tasks, alleviate distress, and realize their aspirations and values. The purpose of social work therefore is to (1) enhance the problem-solving and coping capacities of people, (2) link people with systems that provide them with resources, services, and opportunities, (3) promote the effective and humane operation of these systems, and (4) contribute to the development and improvement of social policy" (Pincus and Minahan 1973, p. 9). A key difference between social work and sociology lies in the emphasis placed on intervention in social work. A social worker expects to be actively involved in the amelioration of social problems, while a sociologist typically focuses on understanding the nature and extent of social issues. Social workers establish a helping relationship with a client system (individual, family, small group...