Structural optimization is a rapidly evolving field with significant applications in various engineering disciplines. This book provides a comprehensive overview of the principles and methods of structural optimization, covering both theoretical foundations and practical applications. It is aimed at graduate students and researchers in mechanical and civil engineering, as well as other fields where structural optimization is relevant. The book is organized into 11 chapters, starting with an introduction to the concepts of structural optimization, followed by discussions on classical optimization tools, linear and unconstrained optimization, constrained optimization, and the optimization process in practice. It then moves on to topics such as sensitivity analysis, dual and optimality criteria methods, decomposition and multilevel optimization, and the optimum design of laminated composite materials. The text emphasizes the importance of developing optimization methods that are compatible with existing structural analysis software, which is essential for practical applications. It also addresses the challenges associated with computational cost and the need for efficient optimization techniques that require minimal interference with existing analysis packages. The book is designed to be used in graduate courses on structural optimization, with suggested coverage depending on the course duration and the students' prior knowledge. It includes exercises and references to facilitate learning and further study. The authors also acknowledge the contributions of various experts who reviewed the manuscript and provided critical feedback. The book is prepared using the TEXTURES software, which is an implementation of the TFX typesetting language.Structural optimization is a rapidly evolving field with significant applications in various engineering disciplines. This book provides a comprehensive overview of the principles and methods of structural optimization, covering both theoretical foundations and practical applications. It is aimed at graduate students and researchers in mechanical and civil engineering, as well as other fields where structural optimization is relevant. The book is organized into 11 chapters, starting with an introduction to the concepts of structural optimization, followed by discussions on classical optimization tools, linear and unconstrained optimization, constrained optimization, and the optimization process in practice. It then moves on to topics such as sensitivity analysis, dual and optimality criteria methods, decomposition and multilevel optimization, and the optimum design of laminated composite materials. The text emphasizes the importance of developing optimization methods that are compatible with existing structural analysis software, which is essential for practical applications. It also addresses the challenges associated with computational cost and the need for efficient optimization techniques that require minimal interference with existing analysis packages. The book is designed to be used in graduate courses on structural optimization, with suggested coverage depending on the course duration and the students' prior knowledge. It includes exercises and references to facilitate learning and further study. The authors also acknowledge the contributions of various experts who reviewed the manuscript and provided critical feedback. The book is prepared using the TEXTURES software, which is an implementation of the TFX typesetting language.