  We propose a strategy to measure the dark matter power spectrum using minimal
assumptions about the galaxy distribution and the galaxy-dark matter
cross-correlations. We argue that on large scales the central limit theorem
generically assures Gaussianity of each smoothed density field, but not
coherence. Asymptotically, the only surviving parameters on a given scale are
galaxy variance $\sigma$, bias $b=\Omega^{.6}/\beta$ and the galaxy-dark matter
correlation coefficient $r$. These can all be determined by measuring the
quadrupole and octupole velocity distortions in the power spectrum. Measuring
them simultaneously may restore consistency between all $\beta$ determinations
independent of galaxy type.
  The leading deviations from Gaussianity are conveniently parameterized by an
Edgeworth expansion. In the mildly non-linear regime, two additional parameters
describe the full picture: the skewness parameter $s$ and non-linear bias
$b_2$. They can both be determined from the measured skewness combined with
second order perturbation theory or from an N-body simulation. By measuring the
redshift distortion of the skewness, one can measure the density parameter
$\Omega$ with minimal assumptions about the galaxy formation process. This
formalism also provides a convenient parametrization to quantify statistical
galaxy formation properties.
