The twentieth century witnessed cycles of waxing and waning interest in and funding for biofuels programs, most of which were wrecked by economic arguments about the high estimated price of any biofuel relative to the actual prices of gasoline and diesel. When the projected costs of biofuels were 10 times the current costs of conventional fuels, R&D programs were essentially blue sky investigations. Toward the end of the first decade of the twenty-first century, that differential was greatly eroded by technical developments and by global trends in world oil prices. Can the economic status of biofuels production be accurately defined-in particular, with ethanol biomanufactured from sugarcane, corn, and (eventually) plant biomass? Is the case for fuel ethanol still dependent on tax incentives and special pleading by some environmentalists and-most importantly-by politicians concerned by global warming or energy security?