2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/105837We review the recent experimental and theoretical progress in the determination of |V_{ud}| and |V_{us}|, and the status of the most stringent test of CKM unitarity. Future prospects on |V_{cd}| and |V_{cs}| are also briefly discussed.40 pages, Proceedings of the CKM 2005 Workshop (WG1), UC San Diego, 15-18 March 2005High Energy Physics - Phenomenologytext