Operational reliability of gas and oil mains, large amount of product loss, the scope of environmental pollution in case of pipelines rupture are largely determined by reliability of valves as well as by PIGs launcher and receiver stations that are expensive equipment of the linear part of gas and oil pipelines. That is why mounting, maintenance and repair of valves as well as PIGs launcher and receiver stations must be under the strictest standards. Here you will find a systematic exposition as to organization and technology of mounting, maintenance, repair and replacement of valves as well as PIGs launchers and receivers of gas and oil mains. Major defects, damages, malfunctions coming up in operating valves as well as PIGs launchers and receivers got all-round consideration in this work. The book may be of help to experts dealing with design, construction, maintenance and repair of gas and oil pipelines, to scientists and researchers, as well as to students and post-graduates of gas and oil universities.