What do we learn from CMB observations
  We give an account, at non-expert and quantitative level, of physics behind
the CMB temperature anisotropy and polarization and their peculiar features. We
discuss, in particular, how cosmological parameters are determined from the CMB
measurements and their combinations with other observations. We emphasize that
CMB is the major source of information on the primordial density perturbations
and, possibly, gravitational waves, and discuss the implication for our
understanding of the extremely early Universe.
