This book addresses problems in structural dynamics and control encountered in such applications as aerospace structures, robotics, earthquake-damage prevention, and active noise suppression. The treatment combines concepts from control engineering (such as system norms and controllability) and structural engineering (such as modal properties and modal models), thereby both revealing new structural properties as well as giving new insights into well-known laws. The techniques discussed will make it easier for structural engineers to design control systems and for control engineers to deal with structural dynamics.