The proceedings of the Third Nikkei Econophysics Symposium, "Business Models in the 21st Century - Risk Management and Expectations for Econophysics," held in Tokyo in November 2004, are gathered herein. Cutting-edge research on the practical application of econophysics is included, covering such topics as the predictability of markets, the analysis of rare events, the mechanism of crashes and bubbles, markets’ correlation and risk management, investment strategy, stochastic market simulations, agent-based market simulations, wealth distribution, and network structures in economics, most of which are beyond the scope of standard financial technology. New market models and financial-data analysis methods are introduced, and dynamic aspects of markets and economy are highlighted. Professionals, researchers, and students will find an invaluable resource in this first book of its kind to summarize the latest work in the field of econophysics.