  These lecture notes comprise an informal but pedagogical introduction to the
well established physics and phenomenology of the cosmic microwave background
(CMB) between big bang nucleosynthesis and recombination. The dominant
properties of the spectrum, temperature anisotropy and polarization anisotropy
of the CMB all arise from this period. We review the physical processes
involved and show how they are related to the observed phenomenology.

Astrophysics