What would cause sudden and complete electrical failure?

Do you have some hands-on help you can get that is auto repair savvy? TEST ALL FUSES FIRST with a test light!.. This next test isn't for a novice!!.. Need some knowledge of auto electrical system wiring!.. Since you say it stalled and **IF it can't be jump started**.... Truck has lost ignition switch power feed circuit...it is supplied from the smaller wire at the starter solenoid and has a fusible link that may have failed!!.. The big red wire at the alternator PLUG IN CONNECTOR is on this same circuit... Test with test light...IF no power there... Link has failed!!... To test further....can jumper from battery positive to that same red wire to see if ignition feed come back... Need to know what you are doing!!!!