The book reviews the literature on the regulation of NADPH oxidase, which is controversial in many areas, and refers specifically to relevant publications from the past 4 years. Main topics are catalytical properties, cofactor requirements and structural components of NADPH oxidase, activation of NADPH oxidase, inhibition of NADPH oxidase, reconstitution and regulation of NADPH oxidase activity in cell-free systems, and pathology of NADPH oxidase.