This book is based on the basic teaching requirement for the course of theoretical mechanics in advanced industrial colleges in the People's Republic of China. The book includes 16 chapters: principles of statics and the free-body diagrams, basic operations with force systems, reductions and resultants of force systems, equilibrium of coplanar force systems, equilibrium of noncoplanar force systems, friction, kinematics of a point, translation and rotation of rigid bodies, composite motion of a