  We present a self-consistent RVB theory which unifies the metallic
(superconducting) phase with the half-filling antiferromagnetic (AF) phase. Two
crucial factors in this theory include the RVB condensation which controls
short-range AF spin correlations and the phase string effect introduced by hole
hopping as a key doping effect. We discuss both the uniform and non-uniform
mean-field solutions and show the unique features of the characteristic spin
energy scale, superconducting transition temperature, and the phase diagram,
which are all consistent with the experimental measurements of high-$T_c$
cuprates.
