2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55890This is a brief introductory review of the AdS/CFT correspondence and of the ideas that led to its formulation. Emphasis is placed on dualities between conformal large $N$ gauge theories in 4 dimensions and string backgrounds of the form $AdS_5\times X_5$. Attempts to generalize this correspondence to asymptotically free theories are also included.20 pages, LaTeX; Based on the talk at Orbis Scientiae '98, Ft. Lauderdale, FL, December 1998; v2: minor correctionsHigh Energy Physics - TheoryHigh Energy Physics - Phenomenologytext