The research into condensed- and compressed-gas lasers, which led to development of excimer lasers, of electron-beam-controlled carbon-monoxide and dioxide lasers, and of high-pressure lasers operating on electronic transitions of inert gases, is reviewed. The physical principles underlying the methods of population inversion in dense gases and of the pumping mechanisms are considered. The parameters of high-pressure pulsed, pulse-train, and cw gas lasers are cited. The use of high-pressure gas lasers in industry are discussed. The emphasis is on the results of investigations carried out at the Lebedev Physics Institute (FIAN) in 1965--1985.