Volume two of the series focuses on the topics of extraction, filtration, heatless adsorption, hydrometallurgical extraction, interfacial phenomena, separation of gases by regenerative sorption, various polymeric membrane systems, such as electrodialysis, ultrafiltration, reverse osmosis. Gas and liquid separations by selective permeation through polymeric membrane, and the origin of separate system. The last topic, as a special feature of interest, provides an analysis of the genesis and development of new separation techniques.