This book summarizes the latest findings in distillation process research conducted by the distillation research team in Tianjin University, with a focus on engineering aspects. In the context of the multi-scale features of the distillation process, it covers three main areas in research and analysis: process modeling, especially macro-scale industrial columns; process mechanisms, particularly meso-scale mass transfer; and process economics, aimed at the analysis of investment and operating costs (especially the energy costs) of entire macro-scale separation systems involving multiple columns. As it addresses the main engineering basis of distillation, it is also a valuable reference guide to vapor-liquid equilibrium analysis, process modeling and enhancement, efficient column-structure design, methods for reducing energy consumption, and the development of hybrid distillation processes.