  QCD predicts the existence of a new partonic Yukawa phase above a critical
temperature $T_c\sim 150$ MeV. I review some of the key observables which will
be used in heavy ion reactions to search for this new phase at RHIC.
Systematics of collective observables ($N_{ch},E_\perp)$, flow patterns, meson
interferometry, jet quenching, and $J/\psi$ suppression are discussed. This
talk is updated with the first data from RHIC.

Nuclear Theory