Seven co-authors of this book describe the best aspects of this field of investigation. Each chapter and its author are as follows: From CAD to CHAOSD: Structural Design and Optimization Techniques (S. Hernández, U. of Coruña), Sensitivity Analysis in Static and Dynamic Problems (S. Kodiyalam, General Electric), Adaptative Finite Element Methods in Computer Aided Engineering (N. Kikuchi y T. Torigaki, U. de Michigan), Entropy-based Optimization Methods for Engineering Design (A.B. Templeman, U. of Liverpool), Mixed Elements in Shape Optimal Design of Structures based on Compliance (R.P.