This chapter presents a different model to that commonly advanced for most mental health treatment. We argue that the socalled "linear model"-the basis of much of our efforts in psychotherapy and also, perhaps inadvertently, in family therapy as well-is limited in its usefulness. Theoretical developments in areas as diverse as physics, biology, meteorology, and mathematics have suggested an alternative way to conceptualize the behavior of complex systems, such as the family. This new field has been labelled as "chaos theory," or more accurately, the science of complexity, because this new science seeks to understand the behavior of complex systems with interrelating parts. Previously, the behaviors of these complex systems were seen as "chaotic," or simply too random to be understood. Now, however, a new body of knowledge is helping unravel the behavior of complex systems.