At least since the 1940s, attempts have been made to construct a theory that would address the way in which ordered arise and behave. Social work practitioners have adopted such popular theoretical models as theory, developed by Ludwig von Bertalanffy and others, which has sought general principles that would apply to biology, psychology, sociology, or any other discipline that sought to explore self-sustaining, open systems (von Bertalanffy, 1968). Similarly, theorists such as Germaine and Gitterman (1981) developed models of social work practice based on an ecological metaphor, which seek broad principles of practice that will apply across different levels of human social systems. Recently, Wakefield (1996a, 1996b, 1996c) critiqued theories as an important basis for social work practice. Wakefield questioned the utility of theory and the empirical basis of the theories. This article responds in part to these critiques by introducing advances in theory that provide a more promising empirical and mathematical basis for studying human systems. During the past two decades, a mixed group of physical, social, biological, and computer scientists have devoted increasing attention to two systems-related disciplines: chaos theory and complexity theory. Often termed dynamics because they seek to understand that change in ways that are not amenable to the linear cause and effect models familiar to social scientists, these theoretical perspectives are thought to have application across a wide range of scientific and social scientific disciplines (Kauffman, 1995; Kiel & Elliott, 1996). This article discusses the disciplines of dynamics - chaos and complexity - in a way that is understandable and relevant to social work practitioners and researchers. This introduction to dynamics will be mostly conceptual in nature, but will involve some mathematics as well. As yet, no general introductory text on dynamics aimed specifically at social scientists exists, although the volume edited by Kiel and Elliott (1996) included solid articles on most of the central issues, including data analysis and theory. For those with a modest background in calculus and a love of math textbooks, either of two books by Devaney (1989, 1992) would constitute an excellent introduction to the mathematics involved. Kaplan and Glass (1995) also gave an excellent introduction, with an emphasis on biological applications. The mathematics is actually a bit more advanced than in the two Devaney texts, but the verbal discussion is easier to follow. Peak and Frame (1994) provided a thorough introduction without using mathematics any more complicated than high school algebra. A number of enjoyable and thoroughly nonmathematical introductions to chaos theory exist, including Gleick (1987) and Briggs and Peat (1989). Kellert (1993) introduced chaos theory in a nonmathematical manner that still manages to catch many of the technical nuances, in addition to discussing its implications for the future of science. Waldrop (1992), Lewin (1992), and Johnson (1995) introduced complexity theory in a similar fashion. After this introduction, the article explores the relevance of dynamics to social work. Some of this exploration will, unavoidably, be metaphorical; theory in the social sciences is only now being developed, and empirical work is still in the stage of basic research. Nevertheless, we hope that this material will provide social workers with new information that will inspire new and more empirical work on the applications of theory to social work practice. Understanding the Meaning of Nonlinear Dynamics and Deterministic Chaos The phrase nonlinear dynamics, like most nomenclature, sounds more intimidating than it really is when you become familiar with the vocabulary and ideas. A dynamical system is a system that changes over time (Devaney, 1992). …