Centrally important to the progress of inorganic chemistry is the application of new physical techniques for determining crystal and molecular structures. Electronic structure, too, can now be explored by a large variety of spectros­ copic techniques, most of them of quite recent origin. Realizing how essential it was to bring together experts in the techniques themselves and those who might use them for their own chemical purposes, Professor Furlani and I began in the early 1970's to organize small meetings at which this kind of interchange could take place. The first, funded by the Italian National Research Council and Ministry of Education, was at Frascati in 1971. It was followed by others at Oxford (1974) and Pugnochiuso (1977), funded under the NATO Advanced Study Institutes programme. Lectures given at the Oxford Advanced Study Institute were published by D. Reidel under the title Electronic States of Inorganic Compounds: New Experimental Techniques. A three­ year interval between these Institutes has proved suitable both for introducing new generations of potential users to the methods and allowing us to incorporate advances in the methods themselves. In fact, since the last Advanced Study Institute in the series several important advances have occurred, particularly in electron, ion and neutron spectros­ copies. We concentrated the course for 1980 on these newer aspects, though the more specialized lectures were prefaced with introductory material for those not familiar with the general principles.