Azapropazone is a chemically unique non-steroidal anti-inflammatory drug (benzotriazine oxide) which has found successful clinical applications in the therapy of a wide variety of arthritic conditions. This book summarizes the progress and critically reviews the clinical use and experimental studies since its introduction 20 years ago. Several studies focus on the physiochemical, pharmacological and toxico­ logical properties of this drug. The studies suggest that it has some unique properties compared with other non-steroidal anti-inflammatory drugs. Among these the novel observations are that azapropazone inhibits several non-prostaglandin-related leucocyte functions, especially superoxide anion production. These serve as a basis for investigations which are reviewed showing the potential for