2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116682In this paper we first survey some basic results in the cohomology of finite groups, and then discuss recent work on constructing free actions of finite groups on products of spheres.To appear in the proceedings of the summer school "Interactions between homotopy theory and algebra" (Chicago, 2004)Algebraic Topology20J06text