LESLIE J. JARDINE Lmvrence Livermore National LaboratOlY Livermore, CA 94551 U. S. A. The Advanced Research Workshop (ARW) on Nuc1ear Materials Safety held lune 8-10, 1998, in St. Petersburg, Russia, was attended by 27 Russian experts from 14 different Russian organizations, seven European experts from six different organizations, and 14 V. S. experts from seven different organizations. The ARW was conducted at the State Education Center (SEC), a former Minatom nuc1ear training center in St. Petersburg. Thirty-three technical presentations were made using simultaneous translations. These presentations are reprinted in this volume as a formal ARW Proceedings in the NATO Science Series. The representative technical papers contained here cover nuc1ear material safety topics on the storage and disposition of excess plutonium and high enriched uranium (HEU) fissile materials, inc1uding vitrification, mixed oxide (MOX) fuel fabrication, plutonium ceramics, reprocessing, geologic disposal, transportation, and Russian regulatory processes. This AR W completed discussions by experts of the nuc1ear materials safety topics that were not covered in the previous, companion ARW on Nuc1ear Materials Safety held in Amarillo, Texas, in March 1997. These two workshops, when viewed together as a set, have addressed most nuc1ear material aspects of the storage and disposition operations required for excess HEV and plutonium (see Fig. 1, Opening Remarks).