2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/181377This set of lectures is an introduction to black-hole astrophysics. The emphasis is made on the phenomenology of X-ray binaries and of supermassive compact objects at galactic centers.58 pages, 4 figures, notes to the lectures given at the School on Particle Physics, Gravity and Cosmology, Dubrovnik, 21 Aug - 2 Sept 2006, references added, typos corrected, to appear in the proceedings of the school, comments welcomeAstrophysicsGeneral Relativity and Quantum Cosmologytext