In recent years, the importance of carotenoids as light harvesting and photoprotective compounds of the photsynthetic apparatus has become apparent. In particular, advances in caratenoid photochemistry have led to significant developments in our understanding of the mechanisms of photsynthesis. This volume is a comprehensive study of the biology, biochemistry and chemistry of carotenoids in higher plants, algae and phototropic bacteria. Emphasis is placed on the photochemistry of carotenoids and the techniques used to study them. Other chapters focus on the nature and distribution of carotenoids in photosynthetic organisms, their biosynthesis and molecular biology, herbicidal inhibition of carotenogenesis and a review of the xanthophyll cycle.