  The Microwave Anisotropy Probe and Planck missions will provide low noise
maps of the temperature of the cosmic microwave background (CMB). These maps
will allow measurement of the power spectrum of the CMB with measurement noise
below cosmic variance for l < 1500. It is anticipated that no further all sky
CMB temperature observations will be needed after Planck. There are, however,
other CMB measurements for which Planck will be not the end but the beginning.
Following Planck, precise CMB polarization observations will offer the
potential to study physical processes at energies as high as 10^19 GeV. In
addition, arcminute scale, multi-frequency observations will allow study of the
early phases of the formation of large-scale structure in the universe.
