This book is written in honor of Prof. Francisco Rodriguez-Reinoso, who has made significant contributions in the area of porous materials such as active carbons and graphenes. It details the preparation of porous materials, including carbonaceous, zeolitic, and siliceous materials, MOFs, aerogels, and xerogels, describing the characterization techniques and the interpretation of the results, and highlighting common errors that can occur during the process. This book subsequently presents the use of modeling based on thermodynamics to describe the materials. Lastly, it illustrates a number of current environmental protection applications in the context of both water and air.