2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/62768An elementary introduction to the principles of algebraic surgery.19 pages. Notes of lecture given at the Summer School on High-dimensional Manifold Topology, ICTP Trieste, May-June 2001. To appear in Vol. 1 of the ProceedingsAlgebraic TopologyGeometric Topology57R67; 55U15; 19J25text