This is the first book in the Selecta, the collected works of Benoit Mandelbrot. This volume incorporates his original contributions to finance. The chapters consist of much new material prepared for this volume, as well as reprints of his classic papers which are devoted to the roles that discontinuity and related forms of concentration play in finance and economics. Much of this work helps to lay a foundation for evaluating risks in trading strategies. fracandscali Note: "The risk of loss in trading securities, futures, currencies, security futures, options, foreign equities and other products can be substantial. Past performance is not indicative of future results."