  For decades, the determination of the mean density of matter(Omega_M) has
been tied to the distribution of light. This has led to a ``bias,'' perhaps as
large as a factor of 2, in determining a key cosmological parameter. Recent
measurements of the physical properties of clusters, cosmic microwave
background (CMB) anisotropy and the power spectrum of mass inhomogeneity now
allow a determination of Omega_M without ``visual bias.'' The early data lead
to a consistent picture of the matter and baryon densities, with Omega_B =
0.039 +/- 0.0075 and Omega_M = 0.33 +/- 0.035.
