In this book, the authors describe how designers evolve their designs through the Design Evolution Cycle. It identifies challenges associated with designing complex systems, such as dealing with multiple conflicting goals, evolving design preferences, nonlinear and nonconvex constraints and goals, continuous and discrete variables, coupled decisions, sub-models with different levels of fidelity, and emergent properties.The book empowers designers to make robust, informed, and iteratively improved decisions in designing complex systems