This book the second volume in the "Springer Series in Biophysics" collects together contributions to the conference on "Biophysics and Synchrotron Radiation" held in July 86 at Frascati. This meeting addressed the advances on the structure of biological molecules obtained by using synchrotron radiation. In fact it was most timely to review the results of the research in biophysics which is rapidly developing at synchrotron radiation facilities. Moreover, there was interest to discuss the new perspectives opened up by the future high brilliance synchrotron radiation sources. With the use of synchrotron radiation, x-ray spectroscopy of biological molecules is firmly established in the techniques of EXAFS and XANES. Contributions to the detailed knowledge of local structure of active sites of metalloproteins by this approach are presented in this volume, together with a number of studies of -the interaction of metal ions with other important biological macromolecular systems. Structural determination of very large biological systems at high resolution, including a protein and its substrate, are reported. The experimental advances in protein crystallography presented here reduce the time for solving protein structures, thus satisfying a major requirement of the rapidly-expanding field of protein engineering.