"The publication of 'World in Transition: Towards Sustainable Energy Systems' is timely indeed. The World Summit on Sustainable Development gave great attention to this challenge, but failed to agree on a quantitative, time-bound target for the introduction of renewable energy sources. The German Advisory Council on Global Change (WBGU) has now produced a report with a global focus; this is essential in view of the global impacts of climatic changes. The report provides a convincing long-term analysis; this, too, is essential, for global energy policies must take a long-term perspective, over a time frame of 50 to 100 years, while providing concrete guidance for decision makers to be implemented now. There is an urgent need to identify paths by which to secure energy supply for the 2.4 billion people who still depend upon traditional biomass, while keeping clearly in view the need to combine this challenge with the prevention of perilous climatic changes. Our one world must close the gap between industrialized countries’ surfeit and developing countries’ poverty. Policies will need to consider both the broader environmental and specific climate exigencies. I recommend this book very warmly to everyone concerned with global energy issues."