Black holes, pregalactic stars, and the dark matter problem; Primordial nucleosynthesis and the gravitino problem; The X-ray background; Cosmology and galaxy formation - an introduction to some recent results; Clean relativistic binaries: some observational consequences of the CM velocity; Relativistic cosmological models; Present and future of high resolution radio observations of active galactic nuclei; The halo puzzle; The microwave background radiation; Soltions and the generation of new cosmologica solutions; List of participants.