2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180228New source classes are expected to appear in the GLAST/LAT Catalog. Here, the problems faced for their identification are summarized, and some key features of the most likely new populations of the $γ$-ray sky are mentioned.Invited plenary talk at the 1st GLAST Symposium, Palo Alto, California, February 5-8, 2007. Submitted for publication with the Conference Proceedings, AIPAstrophysicstext