The acceleration of world demand for energy during the last forty years has led to a projection of future needs far in excess of present capacity, and one which threatens exhaustion of today's conventional sources at some future time. Coupled with this premise is the realization of two inter-related facts: inadequate, uneconomic sources of energy cripple a man, his nation, and his world and lead to insecurity, famine and ignorance; on the other hand, excessive, uncontrolled use of energy sources leads to wastage of resources, pollution and human misery that likewise respects no national boundaries. These dominating concerns led to the selection of the main theme of the Ninth World Energy Conference - 'The Economic and Environmental Challenges of Future Energy Requirements'. This theme was broadly broken down into six main categories: energy needs, sources of energy, energy conversion and utilization, conservation of energy, economics and environmental considerations. A total of 229 formal papers were considered by the several thousand participants who represented more than 60 countries and a number of international organizations at the Conference.