Introduction to the observed Universe. Standard Cosmology. The thermal history of the Universe. Big-Bang nucleosynthesis. The dark matter problem. Galaxies as building blocks of large scale structure. The Microwave Background Radiation. Statistics and dynamics of clusters of galaxies. X-ray emission from clusters. Gravitational lensing. Sunyaev-Zeldovich effect. High-redshift objects: Quasars and radio galaxies. The X-ray Background. Recent determinations of cosmological parameters.
