Any plant or animal material used by humans as fuel is referred to as biomass. Wood is an example of biomass which is used in the form of pellets and briquettes. Biomass feedstock are the substances used to generate energy or develop biofuels. Some of its examples are agricultural waste, municipal waste, sewer sludge and manufacturing waste. These are converted into suitable energy sources using various techniques such as thermal conversion and biochemical conversion. Biomass such as sugarcane and corn are used to manufacture bioethanol or first generation biofuel. Second generation biofuels use energy crops as their resource and third generation biofuels are produced using algae. The process of recycling, reusing, or composing waste materials and transferring them into useful products such as chemicals and fuels is known as valorization. This book strives to provide a fair idea about this discipline and to help develop a better understanding of the latest advances within this field. It consists of contributions made by international experts. This book is appropriate for students seeking detailed information in this area as well as for experts.