(This is the first of a series of articles dealing with the work of control or eradication of a bark beetle (Dendroctorius Monticolae, Hopk) which threatens to destroy the Pine forests of the park and surrounding areas. This, the Solar method of control, was developed in Crater Lake National Park, has passed the experimental stage, and will probably be introduced into other parks or areas where similar infection occurs. Materials for these articles, covering the various phases of the work, have been very kindly presented by Chief Ranger Godfrey, Park rangers, Stetson and F. Solinsky, Ranger Naturalist F. L. Wynd; and information on the life history is from the Park Manual of Information section on Forest Insects prepared by Mr. J. E. Patterson.)