With an emphasis on real-world problems, this book reviews the basics of optimization of frame structures such as trusses, building frames, and long-span trusses. It introduces methodologies and applications to design problems of finite dimensional structures, creating a bridge between the communities of structural optimization in mechanical engineering and the researchers and engineers in civil engineering. It also covers the historical development of the methodologies and theorems on optimization of finite dimensional structures. Readers learn the basic concepts and methods of structural optimization from illustrative examples without difficult mathematics and continuum mechanics.