2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46423I discuss finite-temperature gauge theories as a framework to describe the quark-gluon plasma in the regime of high temperature where the gauge coupling is small, $g << 1$. I review recent progress in the understanding of the long-range physics, with emphasis on the collective phenomena and their consequences for the screening of the gauge interactions. I consider some of the infrared divergences of the perturbation theory, and discuss the physical mechanisms which remove these divergences.8 pages, LaTeX, Invited talk given at the XXXIth Rencontres de Moriond on QCD and High Energy Hadronic Interactions, March 23 -- 30, 1996, Les Arcs, FranceHigh Energy Physics - Phenomenologytext