  In this talk, I discuss how the changes in the QCD vacuum induced by
increasing nuclear matter density affect nuclear properties under normal as
well as extreme conditions. The quark condensate which is the order parameter
for the mode in which chiral symmetry is manifested is expected to change as
matter density or temperature is changed. The topics discussed are ``BR
scaling," its connection to the structure of nuclei in Landau's Fermi liquid
theory and a variety of consequences on such nuclear properties as effective
nucleon mass, nuclear gyromagnetic ratios, $g_A^\star$, axial-charge
transitions in nuclei and on the fluctuations of nuclear matter into the
strange-flavor direction as observed in heavy-ion collisions. I will also
present a simple explanation of the recent dilepton data in the CERN-CERES
heavy-ion experiments involving densities greater than that of nuclear matter
and of the Indiana results on the longitudinally polarized proton scattering
from heavy nuclei, evidencing dropping vector-meson masses in medium which can
be interpreted as signaling an aspect of chiral symmetry restoration in dense
medium. The test of BR scaling provides a bridge between the physics of extreme
conditions (e.g. relativistic heavy-ion collisions) and the physics of normal
conditions which has conventional descriptions, thereby setting the stage for
formulating many-body theory for nuclear matter starting from an effective
chiral Lagrangian.
