provide quantitative measures of these characteristics * Derives equations that translate qualitative considerations to a quantitative description * Employs and explores mass conservation for species and phases * Makes use of Darcy's law along with carefully described boundary conditions to obtain complete mathematical descriptions of subsurface systems * Provides sample physical problems and solutions that illustrate physical and mathematical aspects of multiphase flow and transport Not only will readers better understand general governing equations, they will also be able to apply the equations to specific physical problems involving single and multiphase flow and transport in porous media. Because in-depth knowledge of continuum mechanics, mixture theory, porous media flow, and averaging theory is not assumed, this book is a timely reference for advanced undergraduate students and graduate students; practicing hydrogeologists, engineers, and scientists; and those interested in developing mastery of the important fundamental principles that underlie modeling of multiphase systems.