  Observations of the polarization of the cosmic microwave backround (CMB) have
the potential to place much tighter constraints on cosmological parameters than
observations of the fluctuations in temperature alone. We discuss using CMB
polarization to constrain parameters relevant for distinguishing among popular
models for cosmological inflation, using the MAP and Planck satellite missions
as example cases. Of particular interest is the ability to detect tiny
contributions to the CMB anisotropy from tensor modes, which is fundamentally
limited by cosmic variance in temperature-only observations. The ability to
detect a tensor/scalar ratio $r \sim 0.01$ would allow precision tests of
interesting inflation models, and is possible with a modest increase in
sensitivity over that planned for the Planck satellite, or potentially by
ground-based experiments.
