Large scale production and consumption of biofuel is being promoted by many nations because of its potential for economic, political, and environmental benefits. Biofuels are partially renewable and substituting them for petroleum fuels may reduce emissions of greenhouse gases and other pollutants, and dependency on imported oil. Of special interest is the possibility of widespread use of biofuels such as biodiesel in the transportation sector, especially if integrated with existing and new hybrid and plug-in technologies and emission control technologies such as particle traps. This book provides new research on this field from around the globe.