  These lecture notes cover mainly three connected topics. In the first part we
give a detailed treatment of cosmological perturbation theory. The second part
is devoted to cosmological inflation and the generation of primordial
fluctuations. In part three it will be shown how these initial perturbation
evolve and produce the temperature anisotropies of the cosmic microwave
background radiation. Comparing the theoretical prediction for the angular
power spectrum with the increasingly accurate observations provides important
cosmological information (cosmological parameters, initial conditions).
