Superconducting Cavities for High Energy Accelerators Progress and Prospects

Real progress in applications of radio frequency superconductivity to high energy electron storage rings has been registered recently. It is clear now that this technology will make a significant contribution to the advancement of particle physics in the 10´s to 100´s of GeV-CM energy range. This progress and its foundation are reviewed briefly. While considerable work remains in consolidating present accomplishments into reliable engineering technology, long lead times for significant technological developments make it appropriate to inquire now about the future prospects for this technology. Does this technology have a potential for being useful in a generation of accelerators that can take us into the TeV domain? This question and its associated R/D questions are addressed.