This book describes fundamental upscaling aspects of single-phasetwo-phase porous media flow for application in petroleum and environmental engineering. Many standard texts have been written about this subject. What distinguishes this work from other available books is that it covers fundamental issues that are frequently ignored but are relevant for developing new directions to extend the traditional approach, but with an eye on application. Our dependence on fossil energy is 80–90% and is only slowly decreasing. Of the estimated 37 (~40) Gtonyear, anthropogenic emissions of about 13 Gtonyear of carbon dioxide remain in the atmosphere. An Exergy Return on Exergy Invested analysis shows how to obtain an unbiased quantification of the exergy budget and the carbon footprint. Thus, the intended audience of the book learns to quantify his method of optimization of recovery efficiencies supported by spreadsheet calculations.