This comprehensive review discusses the biosynthesis and catabolism of flavonoids and their regulation in plants. This interesting work approaches the subject matter from both a historical and methodological point of view. It places emphasis on key regulatory enzymic steps in the two pathways leading to the flavonoid basic units as well as the overall pathway within the flavonoid group. This special volume focuses on the known cell-free enzymology at the C15 level, as well as isotopic tracer studies involving the still unknown enzymic steps. This up-to-date text is an excellent resource for all plant physiologists, biological chemists, phytochemists and chemical ecologists.