The transition from today's fossil-nuclear energy system to a sustainable, renewable energy economy will be one of the central tasks of the coming century. This transition requires not only the technical realization of enormous energy-saving potentials and the development of innovative technologies but also new ideas for their application and promotion. Here, scientists, engineers, sociologists, politicians, and political scientists, as well as practitioners, all have a voice. Their common goal is to sharpen the focus on sustainable energy supply and thereby contribute to a departure from our current energy structure. Topics addressed include energy-saving power plants, the future of electricity grids, North-South partnerships for harnessing solar energy potential, and the assessment of future energy needs.