Two lectures introduce biofuels. First lecture presents about the predicted increase in global mean temp. due to CO2 accumulation, potential carbon neutral energy sources such as solar, geo thermal, wind, and tide, and combustion of biomass as a way of providing carbon neutral energy. The second lecture introduces cellulogic biofuels: types of biofuels, US ethonal plants, and the challenges of efficient conversion from biomass to biofuels.