2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/98547This primarily expository article collects together some facts from the literature about the monodromy of differential equations on a p-adic (rigid analytic) annulus, though often with simpler proofs. These include Matsuda's classification of quasi-unipotent nabla-modules, the Christol-Mebkhout construction of the ramification filtration, and the Christol-Dwork Frobenius antecedent theorem. We also briefly discuss the p-adic local monodromy theorem without proof.45 pages; v2: refereed version, minor corrections; to appear in International Journal of Number TheoryNumber TheoryAlgebraic Geometry14F30; 14F40text