A timely overview of all flow and transport processes in which chemical or physico-chemical phenomena are essential, bringing together theoretical and experimental results previously scattered throughout the literature. Includes important industrial applications. A timely overview of all flow and transport processes in which chemical or physico-chemical phenomena are essential, bringing together previously scattered theoretical and experimental results necessary for the understanding of hydrodynamics in porous media. The text begins by explaining the thermodynamics of phase equilibria for multicomponent fluids, physico-chemical models of single-phase and immiscible two-phase flow, based on the macroscopic theory of oil displacement by water. Subsequent chapters are devoted to the theory of two-phase flow with partial miscibility, with partially miscible flows with phase transitions described later on by means of the negative saturation approach.