2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46396A hierarchy of effective field theories is used to separate the contributions from different momentum scales and to calculate the free energy of QCD at high temperature in powers of the coupling constant up to order $g^5$. The behavior of the perturbative series will also be discussed.4 pages, LaTeX using sprocl.sty. Invited talk presented at DPF96 in Minneapolis, August 1996High Energy Physics - Phenomenologytext