2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/36804Several proposals are being developed around the world for an e+e- linear collider with an initial center of mass energy of 500 GeV. In this paper, we will discuss why a project of this type deserves priority as the next major initiative in high energy physics.65 pages, 17 figures, LaTeX, minor erratum correctionsHigh Energy Physics - ExperimentHigh Energy Physics - Phenomenologytext