2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/87687Some facts about 4-spinors listed and discussed. None, well perhaps some, of the work is original. However, locating formulas in other places has proved a time-consuming process in which one must always worry that the formulas found in any given source assume the other metric (I use {-1,-1,-1,+1}) or assume some other unexpected preconditions. Here I list some formulas valid in general representations first, then formulas using a chiral representation are displayed, and finally formulas in a special reference frame (the rest frame of the `current' j) in the chiral representation are listed. Some numerical and algebraic exercises are provided.7 pages, 1 figure, latex2ePhysics Educationtext