Plant secondary metabolites are plant-based natural products that display a variety of pharmacological effects. This book discusses the invaluable bioactivity and multifaceted potential of these compounds. The book describes the physico-chemical and biochemical aspects of the plant secondary metabolites along with the chemistry, therapeutics and future perspectives of these plant secondary metabolites. Moreover, the book also discusses about various sources of plant secondary metabolites, and the metabolite determination through various analytical techniques. It further describes the potential applications of plant secondary metabolites as anticancer and chemo preventive agents, their role as cosmetic ingredients and activity in skin cancer therapy. Further chapters emphasize upon the plethora of roles of plant secondary metabolites, including those as antivirals, anti-bacterial, anti-inflammatory drugs, cardioprotective agents etc. The book culminates with chapters on the impact of certain plant secondary metabolites in plant defence and human healthcare. This book is meant for researchers and students in the field of pharmacology and plant sciences. Moreover, this book is also useful for industry experts especially working in the field of herbal therapeutics.