This grant provides funding for participation in the study of p+A and A+A collisions at the CERN SPS using a focussing spectrometer. The experiments will study single identified particle distributions (pions, kaons, and protons) as well as two-pion and two-kaon correlations for 450 GeV p+A and 200 GeV/nucleon S, Pb+A collisions. Using a small acceptance focussing spectrometer with high resolution TOF, these measurements will obtain excellent momentum resolution, high statistics in the phase space of interest, and good particle identification. The Pittsburgh contribution to the experiment will be for the TOF system, Monte Carlo studies, and data analysis. The work is designed to probe the spatial and temporal extent of the quark-gluon plasma region that is predicted to occur in relativistic heavy ion collisions.