This book is devoted to the study of the dynamics of rotating bodies with cavities containing liquid. Two basic classes of motions are analyzed: rotation and libration. Cases of complete and partial filling of cavities with ideal liquid and complete filling with viscous liquid are treated. The volume presents a method for obtaining relations between angular velocities perpendicular to main rotation and external force momentums, which are treated as control. The developed models and methods of solving dynamical problems as well as numerical methods for solving problems of optimal control can be used for studying the dynamics of aircraft in the atmosphere and spacecraft with stores of liquid fuel, which are rotating around some axis for stabilization. The results are also applicable in the development of fast revolving rotors, centrifuges and gyroscopes, which have cavities filled with liquid. This work will be of interest to researchers at universities and laboratories specializing in problems of control for hybrid systems, as well as to under-/postgraduates with this specialization. It will also benefit researchers and practitioners in aerospace and mechanical engineering.