Book excerpt: Understanding the psychodynamics of groups has derived from the two separate strands of theory and practice, resulting in two separate disciplines: group psychotherapy and group dynamics. Present-day group psychotherapy derives mainly from psychoanalytic theory and Bion's early experiences with wartime groups, and has been developed from the work of clinicians who practice group psychotherapy as a form of treatment. Group dynamics theory and practice, on the other hand, have arisen largely from the work of social scientists like Kurt Lewin, have been researched in the field and in the laboratory, and have been applied to groups as arenas for leadership training and behavioral change. The Visible and Invisible Group synthesizes these psychoanalytic and group approaches to group life and offers practical guidelines to the group psychotherapist. The authors advocate the simultaneous use of two perspectives: the psychoanalytic perspective for observing the "visible" group of people and their interactions, and a General Systems "Field Theory" perspective for observing the "invisible" group-as-a-whole.