This book is the outcome of the NATO Advanced Research Workshop on "Water Treatment Technologies for the Removal of High-Toxicity Pollutants" which was held on 13-16th September 2008 in Kosice, Slovakia. It contains a variety of invited contributions by highly experienced educators and scientists, and is structured to cover important aspects of the field of water treatment from fundamental principles to modelling and policy making. Special attention is given to high toxicity pollutants and among them arsenic which is considered as a high priority one. Methods for treatment are discussed including sorption on nanomaterials. The solution chemistry, toxicity and health effects are also discussed quite extensively. Sociological, ecological and economic aspects needed to develop an integrated approach to solution of water treatment problems are discussed. High toxicity pollutants are a major concern in environmental security and the information in the book covers this area effectively. The book is a valuable resource of information to everyone dealing with related aspects.