1. Introductory background and legislative-regulatory perspectives -- 2. Chlorine dioxide chemistry, reactions, and disinfection by-products -- 3. Generation technologies and general safety -- 4. Application strategies in drinking water -- 5. Inactivation of microorganisms by chlorine dioxide -- 6. Distribution systems -- 7. The measurement of residuals and monitoring strategies -- 8. Drinking water treatment with chlorine dioxide and potential health effects -- 9. Conclusions and future research needs.