Flavonoids are secondary plant products that have previously been shown to be helpful in determining relationships among plant groups. This work presents comprehensively the occurrence, patterns of variation, and systematic and evolutionary importance of flavonoids in the sunflower family (Asteraceae), the largest family of flowering plants (23,000 species). It gathers together the more than 2500 reports of flavonoids in Asteraceae published between 1950 to the present and interprets these data in context of new taxonomic (especially generic) alignments. The authors discuss flavonoid patterns with reference to modern phylogenetic studies based on morphology and DNA data. This book provides, therefore, the most exhaustive synthesis and evaluation of the systematic and evolutionary import of flavonoids ever accomplished for any large family of angiosperms.