2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/98901A discussion is presented of the principle of black hole com- plementarity. It is argued that this principle could be viewed as a breakdown of general relativity, or alternatively, as the introduction of a time variable with multiple `sheets' or `branches' A consequence of the theory is that the stress-energy tensor as viewed by an outside observer is not simply the Lorentz-transform of the tensor viewed by an ingoing observer. This can serve as a justification of a new model for the black hole atmosphere, recently re-introduced. It is discussed how such a model may lead to a dynamical description of the black hole quantum states.Plenary Lecture Notes ICMP97, Brisbane, Australia, July 1997. 12 pages LaTeX, 5 Figures PostscriptGeneral Relativity and Quantum Cosmologytext