The Ninth Annual Conference on Applications of X-Ray Anal­ ysis sponsored by the University of Denver was held August 10, 11,12, 1960, at the Park Lane Hotel in Denver, Colorado. Forty­ one papers on new developments in X-ray analytical techniques and instrumentation were presented. This volume contains thirty­ eight of those papers. Research in X-ray analytical methods is a dynamic and expanding area of scientific investigation. Each year exciting and stimulating progress is reported in the various regions of this field. Suitable documentation of the results is the purpose of the series "Advances in X-Ray Analysis. " Participation in the Conference by two distinguished European scientists, Dr. Raymond Castaing of the University of Paris, France, and Dr. Arnold Hargreaves of the Manchester College of Science and Technology, England, was made possible through financial aid provided by the United States Office of Naval Research. This assistance is greatly appreciated. Major contributions to the conference were made by the following individuals who chaired the technical sessions: Dr. William D. Forgeng, Electro Metallurgical Company, Niagara Falls, New York Dr. Kurt F. J. Heinrich, E. I. du Pont de Nemours and Company, Wilmington, Delaware Mr. Robert A. McCune, University of Denver, Denver, Colorado Dr. Dan McLachlan, Jr. , Stanford Research Institute, Menlo Park, California Dr. William H. Robinson, Carnegie Institute of Technology, Pittsburgh, Pennsylvania Dr.