This book is a comprehensive collection of information on essential oils and their industrial application. It provides reader with a systematic and advanced knowledge of the role of essential oils as natural preservatives and therapeutic agents. Food and pharmaceuticals are two important pillars of human civilization. Plant essential oils and their volatile compounds have been used for preservation as well as for the treatment of human illness for long as traditional practices in biodiversity-rich countries. This book deals with the potential uses of essential oils against insect pests and spoilage microbes of agri-food commodities such as pulses, cereal, fruits, and their shelved products. It also highlights the molecular-assisted engineering of plant essential oils, the pharma-kinetic facet, and their potential in pharmaceutical and aromatherapy. In addition, the book covers recent advances in science and technology such as extraction methods, metabolomics, phytochemical genomics, bioinformatics, conformational dynamics, mathematical modeling, and nanotechnology application. This book is of interest to teachers, researchers, food scientists, capacity builders, and policymakers. Also, it serves as an additional reading material for undergraduate and postgraduate students of agriculture, food, and pharmaceutical sciences.