9 7 7 . ▁He ▁moved ▁to ▁the ▁University ▁of ▁Manchester ▁in ▁ 1 9 8 1 ▁to ▁be ▁Professor ▁of ▁Music , ▁and ▁remained ▁there ▁until ▁ret irement ▁in ▁ 1 9 9 1 . ▁ ▁K emp ' s ▁time ▁at ▁Sch ott ' s ▁brought ▁him ▁into ▁contact ▁with ▁distinguished ▁compos ers , ▁including ▁Michael ▁T ipp ett , ▁Alexander ▁Go e hr , ▁Peter ▁Max well ▁Dav ies ▁and ▁Harrison ▁B irt w ist le . ▁He ▁became ▁an ▁expert ▁on ▁T ipp ett ' s ▁music , ▁and ▁at ▁Aber de en ▁he ▁edited ▁Michael ▁T ipp ett : ▁A ▁Sym pos ium ▁on ▁his ▁ 6 0 th ▁B irth day ▁in ▁ 1 9 6 5 . ▁His ▁time ▁at ▁Manchester , ▁which ▁The ▁Guardian ▁cons iders ▁the ▁" cul min ation " ▁of ▁his ▁career , ▁saw ▁him ▁write ▁a ▁bi ography ▁of ▁T ipp ett ▁in ▁ 1 9 8 4 , ▁which ▁The ▁Times ▁considered ▁" master ly ". ▁He ▁was ▁also ▁a ▁special ist ▁in ▁Paul ▁Hin dem ith , ▁surve ying ▁his ▁work ▁in ▁ 1 9 7 0 , ▁and ▁H ector ▁Ber li oz , ▁editing ▁the ▁Cambridge ▁Opera ▁Hand book ▁on ▁Ber li oz ' s ▁Les ▁T roy ens ▁in ▁ 1 9 8 9 . ▁ ▁In ▁his ▁ret irement , ▁he ▁lived ▁in ▁North ▁London ▁and ▁then ▁Sus sex , ▁but ▁health ▁problems ▁slow ed ▁down ▁his ▁scholar ly ▁output . ▁He ▁died ▁on ▁