2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47989I give a pedagogical introduction to resummation and power corrections, using the thrust variable in electron-positron annihilation as an example, followed by an discussion of issues of predictability in perturbative QCD.13 pages. This preprint summarizes two presentations at QCD and High Energy Hadronic Interactions, XXXIIIrd Rencontres de Moriond, Les Arcs, Savoie, France, 21-28 March, 1998High Energy Physics - Phenomenologytext