The book provides a comprehensive overview on the mechanisms of muscle contraction and non-muscle cell motility at the molecular and cellular leveland also describes a variety of experimental techniques associated with these systems. Recent findings on the regulatory mechanisms of contraction in skeletal, cardiac and smooth muscles as well as on the mechanisms of actin-myosin sliding coupled with ATP hydrolysis are presented. Then, as non-muscle motile systems, protoplasmic streaming and amoeboid movement, based on actin-myosin interactions, as well as ciliary and flagellar movement, based on tubulin-dynein interactions, are treated in detail. Finally, various aspects of cell division movements, where tubulin and actin play an important role, are described.