A lesser talent might have screwed up such an interesting idea. Which is: based on the premise of the Veronese professor who replied to letters addressed to “Juliet Capulet,” write a song cycle using the epistolary form as the framework. It sounds like a semester assignment for an MFA student in English, but Elvis Costello and his accomplices pull it off without sounding pretentious or calculating. Add to the achievement the fact that those “accomplices” are a string quartet whose accompaniment doesn’t come off sounding like treacle, and you’ve got a pleasant surprise on your hands.

To be fair, the literary underpinnings are easily seen, and the music is often beautiful, but both Costello and the Brodskys know the fine line they must walk with this material. Costello’s wit and facility are consistently stronger than they have been in years, and his melodic sense here resembles sophisticated musical theatre in the vein of Stephen Sondheim more than anything else. God forbid anyone call this “classical rock music”; the rhythmic idiom is classical and the deft use of that idiom is to be applauded, but “classical rock music” is, as Costello tells us in his notes, a “junkyard term.” It’s superficial, snobbish and inaccurate.

All of which The Juliet Letters is not. It is, basically, a fine collection of songs composed within an intentional set of limits. One wonders, however, what ideas for the overall theme were discarded, or perhaps not even considered at all. Certainly, a bunch of letters written exclusively to Juliet would be tiresome. After listening to “Taking My life in Your Hands” and “The Birds Will Still Be Singing,” consider the impact of the album as a whole had a theme been developed beyond that of form. If there is a flaw here, and in Costello’s work in general, it is a vague sensation of unfinishedness. His prolificacy is startling, but the result, especially here, is a group of sparks that could have been fanned collectively into a bonfire.

If my criticism sounds like that of an English professor, don’t misjudge all of the above as a dismissal of the album. “Swine” and “This Offer Is Unrepeatable” swing their jagged edges with such agility they’ll have you smiling with recognition, to say nothing of the fact that, on first listening, you won’t realize that the haunting “The First to Leave” and “The Birds Will Still Be Singing” are being delivered from the afterlife.

So The Juliet Letters is good. It’s not a masterpiece, but it is a pleasant anomaly. If you like Elvis Costello, this will make you happy.