2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/23262This is a set of introductory lectures on the behaviour of a directed polymer in a random medium. Both the intuitive picture that helps in developing an understanding and systematic approaches for quantitative studies are discussed.Lecture note, SERC School on "The Physics of Disordered Systems", IMSC, Chennai. 13 pagesStatistical MechanicsDisordered Systems and Neural Networkstext