The present book deals with the development of many novel & rare bioactive flavonoids & biflavonoids isolated and characterized for the first time from medicinal plants using recent techniques and to compile it at a place which have already been reported earlier in our different papers. In addition, classification of flavonoids & biflavonoids, medicinal uses, spectral characteristics, physiological activities, pharmacological properties and possible biological implications with very special reference to their role in obesity have been described in details.