Understanding the why behind change allows us to better plan and implements change in the future. For this reason the literature on change, and change management, is vast and never ending. Yet no particular model of change suits all situations, and no situation is perfectly suited to a particular change model. Theory construction about change varies from the personal to the structural and the sociological. Maslow’s hierarchy of needs is an example of the first, structuration theory the second, and Habermas’ theory of communicative action the third. The use of social theory allows a deep understanding of the underlying social forces at work, with a view to applying those understandings to different settings. This paper’s aim is to take an established theory, Complex Adaptive Systems (CAS) and applying to a hitherto untheorised (but not unresearched) area, the adoption of computers in primary care. It uses as a case study the uptake of desktop clinical information systems (CIS) in Australia in the period 1995-2005, a period in which general practitioner computerization went from effectively nil to 100%. What made many thousands of individual, unconnected practices adopt computers, and what might others learn from this? This paper will describe the principles of CAS, and then the adoption of computer systems within Australia, and then explore the linkages.