Recent progress in Lorentz-covariant quantum field theories of
the nuclear many-body problem (quantum hadrodynamics, or QHD) is
discussed. The effective field theory studied here contains nucleons,
pions, isoscalar scalar (&sigma) and vector (&omega) fields, and
isovector vector (&rho) fields. The theory exhibits a nonlinear
realization of spontaneously broken SU(2)_{L}xSU(2)_{R}
chiral symmetry and has three desirable features: it uses the same
degrees of freedom to describe the nuclear currents and the
strong-interaction dynamics, it satisfies the symmetries of the
underlying theory of quantum chromodynamics, and its parameters can be
calibrated using strong-interaction phenomena, like hadron scattering or
the empirical properties of finite nuclei. Moreover, it has recently been
verified that for normal nuclear systems, it is possible to systematically
expand the effective Lagrangian in powers of the meson fields (and
their derivatives) and to truncate the expansion reliably after
the first few orders. Using a mean-field version of the energy
functional, accurate quantitative results are obtained for the
bulk and single-particle properties of medium- and heavy-mass
nuclei. The importance of modern perspectives in effective
field theory and density functional theory for understanding these
successes of QHD is emphasized.

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