Why do we need a theory of complex systems? And how dare the author (with his publisher's consent, no less) give this book such an audacious title as How Nature Works? While many theories have been proposed to describe individual complex systems, self-organized criticality is the first general theory of complex systems with a firm mathematical basis.<BR>This book, written by the discoverer of self-organized criticality, describes for general readers a concept that has become increasingly important in science. Many seemingly disparate aspects of the world, from the formation of the landscape to the process of evolution, to the action of nervous systems, to the behavior of the economy, all share a set of simple, easily described properties. While it is standard to think of these as "emergent properties," clearly the explanation cannot end there.<BR>What defines an emergent property? Per Bak describes the applications of self-organized criticality in natural phenomena ranging from the study of pulsars and black holes, to earthquakes and the evolution of life.