This book provides a comprehensive presentation of issues and challenges faced by researchers and practicing engineers in motion planning and hybrid control of dynamical legged locomotion. This volume provides a comprehensive overview of hybrid models describing the evolution of planar and 3D legged robots during dynamical legged locomotion and hybrid control schemes to asymptotically stabilize desired periodic orbits for the resultant closed-loop systems. The topics range from hybrid systems, systems with impulse effects, offline and online motion planning algorithms to generate desired feasible periodic walking and running motions and two-level control schemes, including within-stride feedback laws to reduce the dimension of the hybrid systems, continuous-time update laws with a radial basis step length to minimize a general cost function in an online manner and event-based update laws to asymptotically stabilize the generated desired periodic orbits. This volume can be viewed as a handbook in this field, as well as an important reference book for researchers and practicing engineers. It will fill the gap for those who are familiar with the theory and applications of robotics and control systems and serve as a valuable reference and essential guide for researchers and engineers to conduct future research on the development of hybrid control of legged locomotion. The book also serves those who have expertise in one technical area of legged locomotion, but want to increase their understanding of how their expertise may relate to other types of legged robots.