Alargenumberofmathematicalbooksbeginaslecturenotes;but,sincemathematiciansarebusy,andsincethelaborrequiredtobringlecturenotesuptothelevelofperfectionwhichauthorsandthepublicdemandofformallypublishedbooksisveryconsiderable,itfollowsthatanevenlargernumberoflecturenotesmakethetrans