Whileusingthisbookinclasses，wefoundthatourcanonicalreadercanlearnnonquantumphysicsratherquickly.Indeed,equippedwithgeometricintuitionandafacilitywithabstractarguments,heisinapositiontodealdirectlywiththegeneral,currentlyacceptedmodelsusedinrelativitywithoutbeinghandicappedbytheprejudicesthatinevitablycomewithyearsofNewtoniantraininginthestandardphysicscurriculum.However,thisshortcutdoesinvolveaprice:onecannotreallyseethediversityofspecialcasesbehindthedeceptivelysimplefoundationwithoutspendingmoretimethanamathematicsstudentnormallycanorshould.Wehavefeltforalongtimethataseriouseffortshouldbemadebyphysiciststocommunicatewithmathematicianssomewhatalongthelineofthisbook.Westartedwiththeaimofkeepingthephysicshonest,keepingth9mathematicshonest,andkeepingthelogicaldistinctionbetweenthetwostraight.Butwewereill-preparedfortheattendanttraumaofsuchanundertaking.