2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/111726These notes contain a brief introduction to rational homotopy theory: its model category foundations, the Sullivan model and interactions with the theory of local commutative rings.A slight revision (some minor errors corrected) of lecture notes from a minicourse given in the summer school "Interactions between Homotopy Theory and Algebra," August 2004. (28 pages)Algebraic Topology55P60text