It is well known and acknowledged that public policies are inherently complex. But the implications of complexity theory (or complex adaptive systems theory) for policy analysis have not been explored fully. The authors of this volume offer perspectives and methodological tools to fill this gap. Among the questions explored in the volume are, does complexity theory offer a 'new science', an alternative way of thinking to the pervasive rationalism of the mainstream policy analysis, or is it merely a novel analytical tool kit? Does the theory suggest a new way of knowing-and consequently solving-complex public policy problems, for example? How does the theory conceptualize complexity, and is this different from common understandings of the term? What should be the involvement of policy analysts in the process of change from the perspective of complexity theory? Does the theory support or suggest a complexity ethics? The authors of the book also illustrate how agent-based models, the most commonly applied tool of complexity theorists, can be used in policy analysis, as well as creatively applying other methods such as Q-methodology and qualitative case study in understanding complex social problems.