In Complexity, the widely applauded work by Mitchell Waldrop that introduced the exciting and important work of the Santa Fe Institute to a wide audience, Brian Arthur and his ideas played a pivotal role and were shown connecting creatively with the many aspects of the Institute's work. This book brings together Professor Arthur's pioneering articles and provides a comprehensive presentation of his exciting vision of an economics that incorporates increasing returns. After a decade of resis-tance from economists, these ideas are now being widely discussed and adopted, as Kenneth Arrow recounts in his foreword. In fundamental ways they are changing our views of the working economy. The essential ideas are first introduced at a popular level with an article originally published in the Scientific American. They are then shown in powerful and convincing application to a variety of questions, including competition between technologies and the development of industrial clusters such as Silicon Valley. The volume also contains the technical articles that underpin the creation of this important and original work in economics. Brian Arthur's work establishes a whole new domain for economics, a new perspective on many contemporary economic problems, and an explanation for many puzzling features of the high technology economy. This book provides the ideal introduction to and a comprehensive exposition of Arthur's work.