2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46983I give a pedagogical summary of the methods of light-cone variables, rapidity and pseudo-rapidity. Then I show how these methods are useful in analyzing diffractive high-energy collisions.RevTeX, 14 pages, 6 postscript figuresHigh Energy Physics - Phenomenologytext