I can't stop thinking about "Merrily We Roll Along." People say it's Sondheim's "most tuneful" score. That it has Sondheim's best overture. People say Sondheim was tired of the "HE CAN'T WRITE A MEMORABLE MELODY" allegation. So, right before "Merrily," he gave us "A Weekend in the Country," from "A Little Night Music." That melody was so damned hummable, it wedged itself permanently in many, many brains. In "Merrily," famously, Sondheim puts one of his critics centerstage: "How 'bout a tune you can hum? How 'bout a tune you go BUM BUM BUM DEE DOO?" For his opening number, Sondheim thinks hard about the weird, slightly archaic jauntiness in the sentence: "Merrily we roll along." (Sondheim borrowed his title from an old play.) The childlike quality of the sentence--along with the idea of life as traveling, "rolling"--gives Sondheim all he needs for his first t...