In December 1942 the Council on Pharmacy and Chemistry was approached by Col. Otis O. Benson Jr., M. C., representing the commanding general, Army Air Forces, Matériel Center, Wright Field, Dayton, Ohio, in regard to the most effective protective substance for the prophylaxis of sunburn. The problem was as follows: The Matériel Center would like information on the most effective protective substance for the prophylaxis of sunburn. In essence, the problem is as follows: