Bonfiglioli Riduttori, a major supplier of power transmissions in the world market, has commissioned four leading and internationally known experts to write this comprehensive handbook on power transmission. All aspects are treated, from history and mathematical theory through detailed design refinements to quality control in the production process. The book is addressed to all who deal technically with power transmissions, from university students to professional users. The book has five parts. In Part 1, Darle W. Dudley gives a historical overview of the development of power transmission technology over four millennia. In Part 2 Jacques Sprengers presents the underlying mechanical theory. Part 3 is devoted to an in-depths treatment of gears and the gearbox, ranging from sophisticated theory to the practical development of toothed gear wheels, shafts, housings, bearings, and so on. Part 4, by Dierk Schröder, focuses on electric machines in all their forms. Finally, in Part 5, Hajime Yamashina describes the reliability standards set by Bonfiglioli Riduttori and the quality assurance system established to maintain them.