Many people in the world are exposed to chronic arsenicosis through drinking water with consequent health effects. In Italy, the new regulation value for As in drinking water caused the inactivation of old treatment plants, the upgrading of the existing plants and design and construction of new treatment plants. This book was written by the Working Group “Arsenic in water for human consumption” that operated at the University of Brescia (Italy) from 2005 to 2009. The authors of this book have different areas of expertise (geologists, chemists, toxicologists, sanitary-environmental engineers, jurists, biologists). The book gives an overview of As contamination, the analytical methods for As determination, the processes for As removal, four case studies concerning the application of different technologies in real drinking water treatment plants and the criteria recommended for choosing the best available solution for As removal from drinking water. This book is addressed to different types of players: drinking water treatment plant operators, producers of water treatment technologies, public water monitoring agencies and designers of water treatment plants.