This document discusses the history of energy use and the need for conservation and renewable resources. It notes that early humans relied on the sun, their own bodies, and animals for energy but the Industrial Revolution introduced widespread fossil fuel use. Fossil fuels are nonrenewable and their reserves took millions of years to form. As energy demand is projected to double, it is important to conserve energy and explore renewable alternatives like solar, wind, geothermal, and biomass to transition away from fossil fuel dependence for a sustainable future.