Gamma-ray bursts, galactic nuclei and cosmic evolution

Gamma-ray bursts, galactic nuclei and cosmic evolution

Martin J. Rees

This lecture summarises some aspects of gamma-ray bursts, a topic to which Bohdan Paczyński made crucial contributions. It then, more briefly, comments on quasars and active galactic nuclei, where the accretion processes studied by Paczyński and his Polish colleagues play a key role. The lecture concludes with some remarks on cosmology and cosmic evolution.