This 400-page document is available in English and Spanish. The target audience includes environmental health officers and professionals in the fields of water supply, freshwater ecology, public health and health education, as well as for students and consumer groups. This book, which has been prepared by an international group of experts, examines the need to protect drinking water, recreational waters and other water supplies from contamination by toxic cyanobacteria and to control their impact on health. It discusses the nature, diversity and global occurrence of toxic cyanobacteria, their consequences for public health, and methods for the assessment, management, investigation and treatment of contaminated water supplies. Programmes for monitoring the causes and occurrence of cyanobacteria in water and techniques for the analysis of water samples are described.