by Stephen Thomas Erlewine 　　 　　The subtitle of Mercury Nashville's three-disc box set King of the Road is "The Genius of Roger Miller," a sentiment that listeners only familiar with his deliberately silly smashes would dispute, but as this three-disc, 70-track set plays out, it becomes clear that this is hardly hyperbole. If genius is a unique voice, either in writing or delivery, Miller certainly qualifies. If genius is an artist who displays a depth and variety of material, Miller fills the bill. If genius is creating a body of work unlike no other, Miller certainly fits the bill. Miller's genius lay in his command of small details, unassumingly witty wordplay, and seemingly effortless songcraft. Apart from "King of the Road," which developed an iconic status separate from his career, his hits were so funny, so easy, that it seemed his music was too light to withstand such an exhaustive retrospective, but that's hardly the case. Miller's hits were often wonderful, often the pinnacle of his talents, but look closer and it becomes clear that they happened to be the songs that were the singles; he often wrote songs that could have been as big as his hits, but weren't released as singles, or were tucked away on records to be discovered by diligent fans. It's a testament to his talent that not all of these are featured on this otherwise comprehensive box set; the 1991 Country Tunesmith collection alone contains many great songs that could have made the cut. They are missed, as are Miller's brilliant songs from Walt Disney's 1973 animated adaptation Robin Hood ("Not in Nottingham" is as lovely as anything he's done), but that doesn't mean that King of the Road doesn't work as a retrospective -- it just means that, like other great artists, he has more than enough great music to fit onto three CDs. The three CDs are filled with wonderful music -- songs that prove Miller is one of the great country songwriters, capable of songs wrenching in either their humor or pain, and one of the most distinctive voices in the genre. Needless to say, it's essential to any serious country collection.