A review is given of gas absorption which is generally used for the gas with the liq. Gas solubilities and mass transfer concepts used in the design of absorption columns (e.g. Kremser-Brown method), film factor concept, penetration theory, and Chilton-Colburn analogy, etc. are discussed. Design procedure (McCabe-Thiele diagram) is described for the bubble tray absorption columns (Murphree liq. plate efficiency). 66 Refs. [on SciFinder (R)]