In this book, the fundamental of membrane science and technology and their application in water treatment is discussed. These days accessing to fresh water is a real challenge in some parts of the world, and membrane technology plays an important role for producing fresh water from saltwater or wastewater. Membranes offer substantial benefits over other available technologies as they are flexible and compatible with various systems. This book provides in-depth technical knowledge on the basics, applications, and latest developments of membrane science and technology. It has 8 chapters and each chapter contains a comprehensive analysis of a specific aspect of the membrane science and technology. It covers the current status of membrane technologies and a critical overview of new materials and processes, as well as opportunities for future research.