Fluctuations in the cosmic microwave background

The Cosmic Microwave Background (CMB) gives us a snapshot of the universe when it was hotter, denser and simpler than today. It is relic radiation from the Big Bang, left over from the transition from an opaque and ionized primordial plasma to a transparent, neutral gas that eventually cooled enough to form the stars, galaxies and clusters that we observe. In these lectures, I will discuss the cosmological evolution of the CMB and of fluctuations in the photons, dark matter and baryons, producing the patterns that we observe today. I will also discuss the statistical tools we have developed to characterize these fluctuations and use them to derive the impact of various cosmological parameters upon the CMB.