This subject covers sunlight, chromotherapy, infra-red, ultra-violet and other forms of light radiation. It is very doubtful if any of these methods, except sunbathing, has any value beyond what psychological help they may give. The only benefits derived would be produced by the faith one has in them. Sunbathing, on the other hand, is a perfectly natural method of absorbing solar radiation from the sun and should be included in every natural health program. In the beginning, the exposures to the sun should be carefully graduated in order to avoid burning.