2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/78775We give a "modern" version, based on Mori theory, of the classification of birational involutions of P^2 up to conjugacy. The result has been known for more than one century but the classical proofs are not always convincing.9 pages, Plain TeXAlgebraic Geometrytext