The MBR Book covers all essential aspects of membrane bioreactors in water and wastewater treatment, including the working principles of MBR technologies. The book aims to separate science from engineering, in an attempt to avoid confusion and to help readers understand the ideas of MBR. The text is divided into five chapters; the membrane and biological aspects are discussed in chapter 2 along with scientific studies. The third chapter covers the design, operation, and maintenance of MBR, including cost modeling and cost benefit analysis. Chapters 4 and 5 cover the commercial MBR products and their applications for water and wastewater treatment, respectively. The text features industrial case studies, along with useful appendices of commercial and international membrane organizations. The book serves as a a primary reference for chemical, environmental, and process engineers, as well as environmental researchers, natural resources researchers, filtration specialists, water company managers, and consultants.