  A recent development on the working of effective field theories in nuclei and
in dense hadronic matter is discussed. We consider two extreme regimes: One,
dilute regime for which fluctuations are made on top of the matter-free vacuum;
two, dense systems for which fluctuations are treated on top of the "vacuum"
defined at a given density, with masses and coupling constants varying as
function of matter density ("Brown-Rho scaling"). Based on an intricate -- as
yet mostly conjectural -- connection between the in-medium structure of chiral
Lagrangian field theory which is a beautiful effective theory of QCD and that
of Landau Fermi liquid theory which is an equally beautiful and highly
successful effective theory of many-body systems, it is suggested that a chiral
Lagrangian with Brown-Rho scaling in the mean field is equivalent to
Fermi-liquid fixed point theory. I make this connection using electroweak and
strong responses of nuclear matter up to nuclear matter density and then
extrapolating to higher densities encountered in heavy-ion collisions and
compact stars.
