This book covers the mechanical materials as artificial muscles as well as the self-healing and the strain sensor materials as artificial skins, which are indispensable to make soft robots. The mechanical materials include polymers, gels and crystals, with stimulation by light and heat. It not only offers a comprehensive, timely snapshot of current research on mechanically responsive materials, together with manufacture of soft robotics, but also provides with the forefront of the study of mechanical materials for soft robotics.