2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/99871These are notes from the 2003 C.I.M.E. summer school "symplectic 4-manifolds and algebraic surfaces". They cover the same material as the author's (by now ancient) Ph.D. thesis.Symplectic GeometryLectures on four-dimensional Dehn twiststext