2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/150664After summarizing the development of black hole thermodynamics in the seventies, we describe a recent microscopic model. This model suggests that the Bekenstein-Hawking area formula holds for extremal black holes as well as for ordinary (non-extremal) ones. On the other hand, semiclassical studies have suggested a discontinuity between non-extremal and extremal cases. We indicate how a reconciliation has been brought about by summing over topologies.Puri Workshop Talk, December 1996; LaTeX, 15 pages; minor changesHigh Energy Physics - TheoryGeneral Relativity and Quantum Cosmologytext