In recent past there is a resurgence of interest in the study and use of medicinal plants. Many traditional plant based remedies are back in use and find increasing applications as (i) source of direct therapeutic agents, (ii) as raw material base for the elaboration of more complex semi- synthetic compounds, (iii) as models for new synthetic compounds and, (iv) as taxonomic markers for the discovery of new compounds. Based on this rationale the present volume presents 26 research communications based on recent worldwide studies on medicinal plants by eminent scientists broadly directed towards drug development from molecules. Some of the interesting reports included are: Plant based molecular farming for human health; Molecular targets of traditional Chinese medicines used in stroke therapy; New Anti-cancer compounds from medicinal plants; Geraniol biosynthesis in Palmarosa; Immunomodulatory effects of plant extracts; Anti-oxidant properties of Indian medicinal plants; Anti-inflammatory activity of terpenoids of Moringa graggii; Plant proteinases: Their potential as therapeutic drugs; Effects of transdermal essential oil on physiological and behavioral changes in healthy volunteers; Medicinal uses and pharmcological properties of Calotropis procera; Treatment of tropical diseases through marine invertebrates; Passionflower in therapeutics; Medicinal plants for their pest control properties; Gastroprotective effect of Parkia biglobosa; Effect of Plumbago zeylanica on some serum parameters of rat. The contributions are from far and wide including USA, Germany, Spain, China, Brazil, Mexico, Austria, Peru, Italy, Iran, Thailand, Nigeria, Nairobi and India. The volume is aimed at a wide range of audience of phytochemist, ethnobotanist, pharmacologist, medical scientists and other researchers engaged in the search of new bioactives from natural sources.