The Advanced Research Workshop (ARW) on Condensed Matter Re­ search Using Neutrons, Today and Tomorrow was held in Abingdon, Oxfordshire for four days beginning 26 March 1984. The Workshop was sponsored by NATO and the Rutherford Appleton Laboratory. A total of 32 lecturers and participants attended. An objective of the Workshop was to review some dynamic proper­ ties of condensed matter that can be studied using neutron spectros­ copy. A second objective, no less important, was to identify new topics that might be investigated with advanced spallation neutron sources. The twelve lectures reproduced in this volume bear wit­ ness, largely by themselves, to the success of the Workshop in meet­ ing these objectives. The many discussions generated by lecturers and participants meant that, in the event, the objectives were in­ deed amply satisfied. I should like to thank all those who attended the Horkshop for their part in making it so beneficial and rewarding. I am most grateful to Reinhard Scherm, who acted as my advisor in the organisation of the Workshop. The efforts of Mrs. M. Sherwen and Miss J. Harren made light my burden of administrative duties. The preparation of the manuscript for publication was simplified by the assistance of Miss C. Monypenny.