Murray Bowen, MD (1913-1990) developed a new theory of human behavior based upon what he considered scientific in the work of Freud, upon studies in evolution and the natural sciences and upon his own research with families.  First called “family systems theory, Bowen theory is a natural systems theory distinct from general systems theory, from the individual theories of psychiatry and psychology, and from group theories in sociology. This new theory provides alternative ways of understanding and addressing problems in the family, in organizations, and in society. Please see The Center for Family Consultation for an excellent Biography of Murray Bowen and history of Bowen family systems theory. During the study of psychiatry at The Menninger Clinic in Topeka, Kansas from 1946-1954, Bowen read extensively in biology and the study of evolution.  His changing view of human functioning led to development of a research project at the National Institute of Mental Health in which families with a schizophrenic member were studied over a five-year period.  The nuclear family process came alive.  From 1954 to 1959, Dr. Bowen began to define concepts about the family as an emotional system that governs the biology and behavior of individuals.  The first chapters in Family Therapy in Clinical Practice describe early work in defining the difference between conventional theory and this new view of the human as part of a family emotional system. By the time Bowen established The Family Center at Georgetown University in 1959, the basic concepts of theory were organized into two fundamental life forces and eight concepts: the emotional system with its variation in the counterbalance between togetherness and individuality; anxiety and chronic anxiety; levels of differentiation of self; mechanisms of reactivity in the nuclear family; triangles; multigenerational transmission process; sibling position; and emotional cut off.  Differentiation of self and the scale of differentiation, along with six other interrelated concepts, formed the basis for a new view of health and human functioning.  No one concept could be explained by another concept.  No one concept could be eliminated or isolated from the theory.  Clinical families, Bowen’s own family system, and all of human society were studied within the framework of theory. Bowen added societal emotional process, as a last concept, and emphasized the origin of problems in human society in man’s relationship to the natural world. Principles based upon these basic concepts provide a foundation for applications in research, education, psychotherapy, medicine, and personal life. Bowen theory is not a theory about pathology, but about variation in human functioning.  Instead of reducing the explanation of physical illness, for example, to one cause and the affect, natural systems theory provides a framework for understanding facts and factors that impact health and functioning in the family. Any symptoms, be they physical, psychiatric, behavioral, social or societal, are the product of reactions stirred in efforts to adapt to challenges in the natural environment and in the relationship system. Levels of differentiation of self and degrees of chronic anxiety preside over the development of symptoms and over resilience. This theoretical foundation provides the direction for therapy. Applications in therapy, in research, in business and organizations, in life grow out of understanding and using Bowen theory to see the system and one’s part in it.  Steps toward differentiation of self provide operating principles that guide the functioning of individuals in various fields as they learn and apply Bowen theory to solving problems in the family and organization and society.