This book looks at petroleum-based fuels and related materials that are central to the economies of developed and developing countries around the world. However, these resources are finite and expected to enter a period of diminishing availability within the next several decades. To move economies based on petroleum and its feedstocks to fuels and materials that are renewable, environmentally friendly, and of greater availability, the science and engineering communities world-wide are exploring many options. As discussed in this book, principal alternative energy resources that scientists have been exploring are wind, solar radiation, hydropower, geothermal power, coal combined with carbon sequestration, hydrogen, and biomass. In addition, biomass and biologically-generated polymers are attractive renewable feedstocks as energy-producing materials. It appears likely that no single resource will offer the versatility of petroleum in the future. As a result, several complementary technologies are being explored to meet the world's diverse needs for energy and resource materials.