“It’s not a trick, it’s a central principle, which is to treat songs like little one-act plays, where you present a situation and then either resolve it or, if you don’t resolve it, move forward so that by the time you’ve finished the song you’re at a different point than you were—in terms of the story, of the show, of the play—so that each song has a function.”
Stephen Sondheim (quoted on Desert Island Discs, Dec. 31, 2000)