Season 42 of the American Classical Orchestra promises to be nothing short of magnificent. From Haydn’s “Lord Nelson” Mass and transcendent J.S. Bach motets to Mozart, Berwald, and not one but three more Beethoven symphonies—including the thunderous Fifth—the coming season is a feast for the historically curious and the passionately musical alike. These are concerts to circle on your calendar, to bring a friend, and above all: do not miss a single note.