2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/55894Lecture delivered at XXXVI Summer School on Subnuclear Physics at Erice in September 1998. It contains a brief reflection on the development of QFT in late sixties and a discussion of the role of solitons in realistic field theoretic models.Latex2e with amssymb.sty, amsfonts.sty, a4.styHigh Energy Physics - Theorytext