In the framework of the section on Wastewater Treatment and Reuse launched by the Editorial Office of Water, we proposed a Special Issue titled Advanced Oxidation Processes for Water and Wastewater Treatment. One review and nine research papers were published in this Issue of Water from March 2020 to March 2021 a=er a rigorous peer-review. Nonetheless, a printed book gathering them in an organized manner would be very useful. The book format allows one to browse through the articles in a much easier way. Anybody in a laboratory/classroom can have the printed book at hand for consultation at any time. This book contains articles written by several experts on Advanced Oxidation Processes, particularly focused in electrochemical treatments. Its publication will allow the scientific community interested in this domain to possess a book of distinctive value at an affordable price.