This edited volume covers sustainable biomass valorization and its application in various sectors. Bioenergy has concerned enormous attention as a promising alternative to conventional energy resources. Abundance of bioresources and their renewable nature provides a distinct advantage to biofuels from sustainability perspective. Biofuels have found increasing applications in the energy and transportation sector in recent years. Blended fuels are being used worldwide. However, several challenges remain to be addressed due to the diverse nature of biomasses and inherent recalcitrant nature of biological materials used as feedstock. This book aims to provide an overview of recent developments in the production of bioenergy and its applications in various areas. Specific emphasis is given to production of biofuels from modern biomass such as agro-forest waste and dedicated non-edible energy crops that do not interfere with food production. The scope of the book covers synthesis and characterization of biologically derived fuels, advances in microbiological methods and enzyme engineering approaches. The book covers techno-economic analysis to identify challenges and prospects for commercialization of biofuels. The directions for future research should pave way for net zero scenario for a sustainable world. The book will cater to a wide range of readers interested in learning the fundamentals as well as advances in the field of biofuels.