Bioenergy is a form of renewable energy that is derived from biological sources. Biomass is a plant or plant-based material that is used directly via combustion to produce heat or indirectly after conversion into biofuel. Such conversion of biomass to biofuel is achieved by different thermal, chemical and biochemical methods. Biomass fuels are usually a by-product or residue of forestry, farming or animal husbandry. Various solid and sewage biomass are used as sources of energy. Solid biomass includes manure, garden waste and crop residues. Some agricultural products like corn, soya bean, sugarcane, jatropha, sugar beet, etc. are specifically grown for biofuel production across the world. Some examples of biofuels are bioethanol, biodiesel, biofuel gasoline, etc. This book aims to equip students and experts with the advanced topics and upcoming concepts in the field of bioenergy. As this field is emerging at a fast pace, this book will help the readers to better understand the concepts of biomass and biofuels. This book will help new researchers by foregrounding their knowledge in this domain.