Book excerpt: This book presents recent advances in the integration and the optimization of product design and manufacturing systems. The book is divided into 3 chapters corresponding to the following three main topics : - optimization of product design process (mechanical design process, mass customization, modeling the product representation, computer support for engineering design, support systems for tolerancing, simulation and optimization tools for structures and for mechanisms and robots), -optimization of manufacturing systems (multi-criteria optimization and fuzzy volumes, tooth path generation, machine-tools behavior, surface integrity and precision, process simulation), - methodological aspects of integrated design and manufacturing (solid modeling, collaborative tools and knowledge formalization, integrating product and process design and innovation, robust and reliable design, multi-agent approach in VR environment). The present book is of interest to engineers, researchers, academic staff, and postgraduate students interested in integrated design and manufacturing in mechanical engineering.