[en] Contract AC02-85ER40193 supports an investigation of hadronic matter at very high energy densities. The present experiment, E-735, is a search for a deconfined quark-gluon plasma phase of hadronic matter predicted to occur when temperatures of 240 MeV are achieved. Preliminary data were obtained during the first operation of the Fermilab Tevatron Collider during the period January to May 1987. Based on these data the collaboration has published first results on the charged particle multiplicity and transverse momentum distributions. In addition, we have data on the particle identification of the produced secondaries, and publications are in preparation. Both measurements are regarded on theoretical grounds to be sensitive indicators of the formation of a high temperature plasma. We are currently in the principal data acquisition phase, which began in the spring of 1988. We now have in place our complete detector, including the central tracking chamber. Tests will also be made on backgrounds and detector materials appropriate to our proposal, P-787, to measure leptons and photons in the third Collider running period