2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191575We briefly review the theoretical status and the open theoretical challenges in the physics of heavy quarkonium.To be published in Acta Physica Polonica, based on the invited talk given at 31st International Conference of Theoretical Physics: Matter to the Deepest: Recent Development in Physics of Fundamental Interactions, Ustron, Katowice, Poland, 5-11 Sep 2007. References addedHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext