The book contains an original method for calculating parts of machines of complex configuration, based on studies of moment deplanation of sections. New generalized strength criteria for complex machine parts are experimentally justified and formulas for determining stress concentration coefficients are given. For parts transmitting forces by means of friction contacts, stability of these contacts and distribution of stresses in adjacent zones are investigated. The book discusses the features of calculation of impact systems with details of complex configuration and gives promising directions for application of the proposed calculation methods. The book is intended for engineering and technical workers involved in calculating parts of machines and structures and assessing their strength and reliability.