This volume belongs to the series of the HERCULES Course on Neutron and Synchrotron Radiation for Condensed Matter studies. This course, coorganized by Universities in Grenoble and Paris, CNRS and INSTN, takes place since 1991 in Grenoble, elose to and with the support of the European Synchrotron Radiation Facility (ESRF) and the Institut Laue Langevin (ILL). The first volume gave general presentation of the theory, instruments and methods used in the fields. This second volume, which corresponds to a two-week course, is devoted to selected applications in Physics and Chemistry of Solids. This domain of applications is extremely wide and no attempt has been made to cover it entirely. It ineludes fourteen chapters, from general considerations on symmetry in condensed matter to the most recent developments on magnetic excitations and electron spectroscopies in high Tc superconductors. The subjects have been chosen, either for their basic importance or in relation with recent developments. The fifteen authors have been selected on account of their high scientific level and teaching skills. Among them, Jean Rossat-Mignod passed away suddenly in August 1993, and we would like here to honor his memory: he was a very deep physicist and an excellent expert of the applications of neutron techniques to various fields, of condensed matter physics, such as magnetism, correlated metals, superconductivity and phase transitions.
