2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190781We give an outline of a recent proof that the low-energy effective gauge theory exhibiting quark confinement due to magnetic monopole condensation can be derived from QCD without any specific assumption. We emphasize that the low-energy effective abelian gauge theories obtained here give the dual description of the same physics in the low-energy region. They show that the QCD vacuum is nothing but the dual (type II) superconductor.15 pages, Latex, no figures, Talk given at YKIS'97, Non-perturbative QCD, KyotoHigh Energy Physics - TheoryHigh Energy Physics - Latticetext