Much of our present material prosperity depends on an abundant supply of coal, gas, and oil, which provide energy to operate our machines. These fossil fuels, like uranium, are limited in quantity and are essentially irreplaceable. Although the world will not suffer a shortage of fuel in our generation, we cannot blithely assume that our descendants can continue indefinitely to have all the fuel that they need. Rapidly increasing populations and the still more rapidly increasing demands for electricity and other forms of power throughout the world leave thoughtful people with an impression of solemn responsibility for the needs of future generations. Nearly 2,000 times as much energy as is needed for daily fuel requirements falls on the geographical area of the United States, the most energy-consuming country in the world. Although it is now difficult to make practical use of this sunlight, it is not impossible. The experimental field requires the co-operation of many sciences- chemistry, engineering, physics, meteorology, botany, and architecture, to cite only a few. This book spotlights present achievements and expected advancements in solar energy research and in its text and bibliography provides some of the help which scientists, engineers, and inventors need as a basis to advance fundamental knowledge in unpredictable directions. The results of present experimentation with solar energy may eventually change the living habits and work routines of many people. Homes heated with solar energy have been constructed experimentally, and solar air conditioning holds promise for the future. To exchange ideas about their research, a group of scientists met in 1953 for a symposium on solar energy organized by the University of Wisconsin and sponsored by the National Science Foundation.