Sir Charles Mackerras turned 80 while standing on the podium of the Royal Opera House this weekend, and while he is by no means alone in the ranks of living octogenarian conductors, there is little question that the career he has built in his six decades in the music business is the envy of the orchestral world. What makes Mackerras almost unique among conductors is his diversity of interests: “[perhaps no] other conductor has acquired quite so many specialties or put them into practice with so many ensembles.”