The concerns relating to global warming, climate change, and increasing energy demands have led to significant research towards the development of alternative energy to substitute the fossil energy sources. Biomass-based energy or biofuels are highly promising due to many perceptible environmental and socio-economic advantages. Cutting-edge academic research and advanced industrial product development have created tremendous scope for the implementation of biofuels at a global scale to reduce the greenhouse gas emissions and supplement the escalating energy demands. The prime focus of this book is to provide an overview of the different technologies utilized to harness the chemical energy from plant-based non-edible biomass and other organic wastes in the form of solid, liquid, and gaseous biofuels. The opportunities and challenges of different biomass conversion technologies, especially biomass-to-liquid, biomass-to-gas and gas-to-liquid routes, as well as biomass pretreatments, densification, anaerobic digestion, reforming, transesterification, supercritical fluid extraction, microalgal carbon sequestration, life-cycle assessment and techno-economic analysis have been comprehensively discussed in this book. This book is an amalgamation of fifteen different chapters each with distinctive investigations and a collective focus relating to the transition from fossil fuels towards carbon-neutral biofuels. This book serves as a benchmark for academic and industrial researchers involved in exploring the true potentials of plant residues and waste organic matter to produce alternative renewable fuels. To realize the real promises of bioenergy, this book attempts to assess the biorefining approaches, biofuel production and application, and environmental sustainability.