Contaminated drinking water contributes to disease in developing and developed countries worldwide.  This book, which is the outcome of a shared WHO-OECD initiative since 1998, provides a state-of-the-art review on approaches and methods used in assessing the microbial safety of drinking-water.  It supports a framework for water and offers guidance on the selection and use of available indicators alongside operational monitoring to meet specific information needs. It looks at potential applications of new technologies and emerging methods.