  We study the prospects for extracting cosmological and astrophysical
parameters from the low radio frequency 21-cm background due to the spin-flip
transition of neutral Hydrogen during and prior to the reionization of the
Universe. We make use of the angular power spectrum of 21-cm anisotropies,
which exists due to inhomogeneities in the neutral Hydrogen density field, the
gas temperature field, the gas velocity field, and the spatial distribution of
the Lyman-$\alpha$ intensity field associated with first luminous sources that
emit UV photons. We extract parameters that describe both the underlying mass
power spectrum and the global cosmology, as well as a set of simplified
astrophysical parameters that connect fluctuations in the dark matter to those
that govern 21-cm fluctuations. We also marginalize over a model for the
foregrounds at low radio frequencies. In this general description, we find
large degeneracies between cosmological parameters and the astrophysical
parameters, though such degeneracies are reduced when strong assumptions are
made with respect to the spin temperature relative to the CMB temperature or
when complicated sources of anisotropy in the brightness temperature are
ignored. Some of the degeneracies between cosmological and astrophysical
parameters are broken when 21-cm anisotropy measurements are combined with
information from the CMB, such as the temperature and the polarization
measurements with Planck. While the overall improvement on the cosmological
parameter estimates is not significant when measurements from first-generation
interferometers are combined with Planck, such a combination can measure
astrophysical parameters such as the ionization fraction in several redshift
bins with reasonable accuracy.
