This book reviews of up-todate conversion techniques for biofuels. It emphases on the cutting-edge development for the production of liquid and gaseous biofuels that should be useful to the chemical scientists and technologists. A biofuel is a fuel that is produced through contemporary biological processes, such as agriculture and anaerobic digestion, rather than a fuel produced by geological processes such as those involved in the formation of fossil fuels, such as coal and petroleum, from prehistoric biological matter. Bioenergy is energy derived from biofuels. Biofuels may also be derived from forestry, agricultural or fishery products or municipal wastes, as well as from agro-industry, food industry and food service by-products and wastes. Generally, bioenergy covers roughly 10% of the total world energy demand. Traditional unprocessed biomass such as fuelwood, charcoal and animal dung accounts for most of this and represents the main source of energy for a large number of people in developing countries who use it mainly for cooking and heating. More advanced and efficient conversion technologies now allow the extraction of biofuels from materials such as wood, crops and waste material. Bioenergy consists of solid, liquid, or gaseous fuels. Liquid fuels can be used directly in the existing road, railroad, and aviation transportation network stock, as well as in engine and turbine electrical power generators. Solid and gaseous fuels can be used for the production of electrical power from purposedesigned direct or indirect turbine-equipped power plants. Around 85% of the liquid biofuels are currently produced in the form of bioethanol with the main producers being Brazil and the USA. Biodiesel production is essentially concentrated in the European Union. Commercial biomass conversion technologies are improving, with respect to efficiency of resource use, and environmental impact mitigation and economic performance. This book should be of highly immense valuable tool for researchers, academicians and industrialists.