TheinspirationforthisbookwasacourseoflectureswhichIdeliveredbetween1977and1980toundergraduatesabouttoentertheirfinalyearinPhysicsandTheoreticalPhysicsatCambridge.Theaimofthecoursewastoprovideasurveyofthenatureoftheoreticalreasoninginphysics,whichwouldputtheminareceptiveframeofmindfortheveryintensivecoursesoflecturesonallaspectsofphysicsinthefinalyear.TheobjectivesofthecoursearedescribedinthefirstchapterandconcernissuesaboutwhichIfeelverystrongly:studentscangothroughanundergraduatecourseinphysicswithoutgaininganunderstandingoftheinsights,approachesandtechniqueswhicharethetoolsoftheprofessionalphysicist,letaloneanimpressionoftheintellectualexcitementandbeautyothesubject.ThecoursewasintendedasanalternativetothenormalmodeofpresentationandwasentitledTheoreticalConceptsinPhysics.