2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41855Basic developments in the analytic study of the QCD vacuum structure and of the QCD spectrum, including glueballs and hybrids are reviewed.LATEX2e, 10 pages, Invited talk at the conference Q2002, June 2002, Novgorod, RussiaHigh Energy Physics - Phenomenologytext