This volume is the proceedings of the William Harvey Research Conference held in Cannes, France, on the 20th and 21st March, 1997. It describes the present knowledge of the structures of the cyclooxygenase isoforms and the experimental and clinical effects of selective inhibitors of cyclooxygenase-2. The pathophysiological significance of the cyclooxygenase enzymes in tumorigenesis, programmed cell death, vascular disease and asthma is also covered.