The paper presented here is another attempt made to suggest a general classification of separation methods. By the unique classification criteria, which are phase transformations and interfacial transfers, all separation methods of homogenous mixtures of substances are divided into five groups: -methods that are based on the formation of new phases by substances to be separated; -methods that are based on differences in the interphase distribution processes, chromatographic methods being singled out as a separate group; -membrane methods that are based on induced transfers of substances from one phase into another one across a third phase, which separates the two; -separation methods within a single phase that are based on velocity and direction differences in spatial displacement of particles of substances to be separated within one fluid phase under the action of various fields; -combined methods that are based on different combinations of classification criteria for the previous groups above. Descriptions