2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/114566In this paper I briefly review recent progress in the field of ground-based gamma ray astrophysics.Invited review, to be published in the proceedings of the Vulcano Workshop 2006 "Frontier Objects in Astrophysics and Particle Physics", F. Giovannelli & G. Mannocchi (eds.), Italian Physical Society, Editrice Compositori, Bologna, Italy. Final versionAstrophysicstext