Thistextbookcontainsnonewscientificresults,andmyonlycontributionwastocompileexistingknowledgeandexplainitwithmyexamplesandintuition.Ihavemadeagreatefforttocovereverythingwithcitationswhilemaintainingafluentexposition,butinthemodernworldofthe‘electronandtheswitch’itisveryhardtop