The 2nd edition of the textbook contains information on the theoretical foundations of friction, wear and lubrication, on tribotechnical materials (structural and lubricating) and rational technologies for obtaining wear-resistant antifriction and friction coatings and surface layers on various elements of friction units and machine parts, practical recommendations for the calculation, design, manufacture, testing and operation of friction units of various classes and purposes. The most dangerous and harmful types of wear (abrasive, adhesive, hydrogen), which lead to negative technical and economic consequences, are considered.