Recent events highlight the importance of energy generation and distribution of power in today's society. It is clear that while additional large-scale power generation will have to address long-term societal issues such as safety and environmental impact, enhancing the efficiency of our day-to-day devices (transport, heating/refrigeration, home electronics, etc.) requires mainly the development of new materials with improved properties. This MRS volume, first published in 2002, focuses on materials issues in the low-scale generation, storage and transport of energy-photovoltaics, batteries, fuel cells and other small-scale devices. Materials limitations of these technologies are also addressed. Topics include: lithium batteries; hydrogen fuel cells and hydrogen storage; materials for solar energy; solid oxide fuel cells; materials for power in space; disordered and nanoscale materials for energy applications; and thermoelectrics.