2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130671This is an introduction to Grothendieck's descent theory, with some stress on the general machinery of fibered categories and stacks.114 pages. I have corrected a finite, but extremely high, number of errors that have been pointed out to me by various readers. These were mostly typos, but a couple were substantialAlgebraic GeometryCategory Theorytext