Volume 7 of Developments in Applied Spectroscopy is a collection of forty-two papers selected from those that were presented at the 7th National Meeting of the Society of Applied Spectroscopy, held (in place of the 19th Mid-America Symposium on Spectroscopy) in Chicago, May 13-17, 1968. These papers, selected by the editors and reviewed by persons knowledgeable in the field, are those of the symposium type and not those pertaining to specific research topics that one would expect to be submitted to a journal. It is the opinion of the committee that this type of publication has an important place in the literature. The relatively large number of papers would result in quite a sizable volume if bound in one set of covers. For this reason, and to present the material in areas of more specific mterest, Volume 7 was divided into two parts, Part A, Physical-Inorganic, and Part B, Physical-Organic Developments. The 7th National Meeting was sponsored by the Chicago Section as host in cooperation with the St. Louis, New England, Penn York, Niagara-Frontier, Cincinnati, Ohio Valley, New York, Baltimore-Washington, North Texas, Rocky Mountain, and Southeastern Sections of the Society for Applied Spectroscopy and the Chicago Gas Chromatography Group. The editors wish to express their appreciation to the authors and to those who helped with the reviewing. The latter include Dr. Elma Lanterman, Mr. John E. Forrette, Dr. Carl Moore, Dr. B. Jaselskis, Mr. H. G. Zelinski, Mr.