2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149220This essay is a tour around many of the lesser known pregeometric models of physics, as well as the mainstream approaches to quantum gravity, in search of common themes which may provide a glimpse of the final theory which must lie behind them.50 pages, TeX (two references added)High Energy Physics - Theorytext