The Genius.

Although he performed and recorded many duets during his nearly six-decade career, this album of nothing but Ray Charles paired face-to-face in the studio with a pantheon of respected artists is the first all-duet album he ever made. And it was his very last recording, completed less than three months before he died in Los Angeles, June 10, 2004, at 73.

The reason for the odd figures in sound and performance awarded above, and the unusual way of quantifying this album, is because it is more like a dozen distinct recordings, of varying quality, with three different producers, a core band but many musicians, some overwhelming orchestration, one live number, all over nine months of the last year of Charles’ life.

Throwing two giants into the same room is fascinating but usually doesn’t result in their best work. But in a nutshell, if you don’t have this disc, you’ll miss a few of the most poignant recordings The Genius ever laid down. And while this amazingly innovative musical chameleon took on a distinctly different persona for every one of these pairings, what’s so interesting to hear is how nearly every one of the other artists seems compelled to try to come up to Charles’ level and give the very best they have.

Let’s get the bad news out of the way first, the big disappointment: the live duet with Van Morrison, on his chestnut “Crazy Love,” the first recording made but the album’s closer, the one a lot of people looking at the line-up would have most anticipated, is a big zero. What can I say? Morrison is mercurial. Nothing special came out. Now we’ll never have another chance. Get over it.

The album’s opener, though, is charming enough to earn a Grammy nod: Charles and the disarmingly good Norah Jones bittersweetly lamenting “Here We Go Again.” Singling out this one was more political than musical. Jones is still hot. She’s loved. She gives a great performance. But this isn’t even the fifth-best song on the disc. I’ll tell you what is super-funky here, though: Mr. Billy “Beatle” Preston mining his gospel roots and just squeezing the soul out of a Hammond B3. With all due respect, Mr. C, you got upstaged. The most inspired voice on this cut is Preston’s organ. He wails a grand crescendo mid-song that’s mind-blowing, initially for its grandiosity but more importantly for its heavenly singing soul. In the company of genius, indeed.

This is followed immediately by the album’s biggest miscalculation. How’d Sweet Baby James Taylor sneak in here? Tryin’ to funk along on “Sweet Potato Pie” with his Martha’s Vineyard smooth-as-a-baby’s-buttness? Even Charles sounds like he’s savin’ it for later.

Charles and Diana Krall teaming on “You Don’t Know Me” sounds potent, but isn’t. Nothing much comes from Elvis C’s lady, and Charles kinda cruises to match. Still, it has its moments.

Next up: Ray Charles meet Elton John, for the first time. Legendary producer Phil Ramone nearly drowned this duet in horrible strings and truly treacly guitar, but as mostly a non-fan of the Bitch, I was deeply impressed and touched with what both singers did with an Elton John staple. With these two incredibly famous pianists in the room, who plays? Neither. Jazz gem Alan Pasqua was more than up to the task.

So one of the best numbers is followed by one of the worst, followed by one of the best. Let’s just say that Natalie Cole doesn’t have a clue what to do with “Fever,” and Charles can’t bail it out despite some charming vocalisms. Ms. Cole, go to the back room with Mr. Taylor and listen some more to your daddy’s records, like Charles did, then both of you go out and enjoy your money, but please don’t try to hang with the real singers.

Speaking of which, a fine example of soul being more important than pipes is Bonnie Raitt’s fine coworking of “Do I Ever Cross Your Mind,” another of the cuts where both Charles and his partner seem really inspired by each other. But before either one of them even opens a mouth, Raitt’s slide guitar gives Preston’s B3 a run for the money as one of the most achingly gorgeous voices on the whole disc. And no strings in the way.

No, they save the strings all for the next two numbers. We can thank producer John Burk for spearheading this project, but Johnny, French horns and violas are your drugs of choice, eh? No matter, these two classics resist ruination. And let’s not forget, Charles drowned “Georgia” in strings and people recoiled in horror, but it was exactly what was needed.

It’s quite possible Charles and his dear friend Willie Nelson were not actively considering their places in music history with “It Was a Very Good Year,” and their juxtaposition with the Jersey crooner who owns this song and the weight of the autumn of their years and so on, but we can’t avoid it, especially since we know what Charles maybe didn’t, just how short his autumn was at that point. But certainly it at least informs their performances, and if you care at all about either of these guys (both of whom could outsing Frank in their sleep), you can’t help but be moved. It was a very good year, indeed.

Despite an arrangement that would make Dionne Warwick gag, Goffin-King’s “Hey Girl” becomes magic in the hands of perhaps the two most soulful voices on the planet, Charles and Michael McDonald. Sure, throughout the album, Charles’ voice shows a little wear from age and probably declining health, but this is a textbook demo that a great singer can make the phone book sound like high art. (I will never, ever forget hearing Patti LaBelle sing the alphabet on “Sesame Street” in the early ‘70s.)

Neither B.B. King nor Charles have ever sounded much bluesier than they do on “Sinner’s Prayer” -- need I say more? Oh, and please put Lucille in with Preston’s B3 and Raitt’s slide. Just when you question whether King should really be considered top of the heap among all the great blues player-singers in history, you hear him sting off a very few notes that say it all. Oh, and Preston’s back here in glory, praise the Lord.

You’ll want to hear how Charles and Johnny Mathis handle “Over the Rainbow,” but don’t expect much from Mathis. He seems to be the only one who altered his style not a whit because of Charles’ influence. Maybe the guy just can’t get down. This is one where Charles flying solo would’ve been more interesting than what we got.

I’ve sometimes tended to underrate Gladys Knight (though her fellow performers never do), but she takes it to church here in “Heaven Help Us All,” with Charles more in the background and some great gospel choir vocals doing the trick. Preston shows up, too. Thank you, Jesus. (No, really.) Note that both the CD’s back cover and booklet switch the order of “Heaven” and “Rainbow.”

The enhancement on this CD is a five-minute clip from a photo shoot Charles did with Norman Seeff, the famed photographer of musicians, in 1985. Charles philosophizes with Seeff about the character of instruments and the nature of singing. It’s a pretty small coda for such an enormous career and its final recording, but it is real and personal and profound. Just like The Genius.