2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194989The role of instantons in describing non-perturbative aspects of globally supersymmetric gauge theories is reviewed. The cases of theories with N=1, N=2 and N=4 supersymmetry are discussed. Special attention is devoted to the intriguing relation between instanton solutions in field theory and branes in string theory.Latex 170 pages, several figures, uses svmult.cls. v2: minor corrections, references added. Contribution to the volume "String Theory and Fundamental Interactions", dedicated to Gabriele Veneziano on his 65th birthdayHigh Energy Physics - Theorytext