Contemporary realist theory starts from the premise that the international system is "anarchic," as if anarchy were somehow an anomalous condition. But in a discussion of complex systems such as biology and the stock market, John Holland and his colleagues at the Santa Fe Institute have argued that order often emerges out of unordered systems. Work on "complex adaptive systems" suggests that the behavior of most biological systems is not centrally controlled. Indeed, lack of centralized control is what makes the system more adaptive in the long run. In fact, most biological and social systems are anarchic, a condition that nonetheless permits substantial self-organization. This work is highly suggestive for the social sciences, offering an explanation why central planning has given way to markets. A further implication may be that there can be no deterministic model for the behavior of international systems, and that theorists who have been chasing elegant and highly reductionist models of international relations are doomed to fail. While written for non-mathematicians, the book remains hard going because of its abstractness. This is, none-the-less, a body of ideas that needs to be considered by those who think about the international system.