This is a translation of a scuba diving manual originally published by the publishing house of the U.S.S.R. Ministry of Defense. The manual contains information, practical recommendations and informative data on underwater exploration and repair of various types of scuba diving equipment; the technique of water safety and the execution of underwater work; medical precautions and specific illnesses of scuba divers; the method of instruction, including the technique of underwater swimming and the execution of light diving work, underwater hunting, photo- and cinematography. The manual was designated for divers of the Soviet Army and Navy and the transportation and commercial fleets. It is also of interest to a wide circle of readers interested in problems of the underwater sport.