In celebration of what would have been the 75th birthday of Ray Charles, Rhino is releasing two albums by the icon Sept. 20: a collection of duets called "Genius and Friends" and a mammoth, 146-track boxed set of his seminal work, "Pure Genius: The Complete Atlantic Recordings (1952-1959)," which includes never-before-released rehearsal tracks.

Charles, who would have been 75 on Sept. 23, died June 10, 2004. Before his death, he asked the label to complete and release the duets project.

An earlier album of duets, "Genius Loves Company," released last year on Concord, has racked up triple-platinum sales (3 million copies sold). Rhino execs, looking at the platinum award for their soundtrack to the 2004 hit biopic "Ray" and the gold status that the album "The Very Best of Ray Charles" has achieved, expect good things for both new sets.

"The box set is sort of a hello from when Ray made his astounding early 45s on Atlantic," said Mike Engstrom, Rhino's vice president for marketing. "The duet album is a final goodbye."

The new duets album has Charles singing with Jill Scott, Mary J. Blige, Chris Isaak, Patti LaBelle, Diana Ross, George Michael and Angie Stone. He also teams up with soul man John Legend, Italian pop star Laura Pausini and Idina Menzel, star of the Broadway musical "Wicked."

Rhino rounded out the album with two tracks originally recorded for other purposes: Alicia Keys's performance of "America the Beautiful," a tune associated with Charles, at last year's Super Bowl halftime show, and Charles singing "Busted" with buddy Willie Nelson for a 1991 TV special. Keys is accompanied by 150 students from the Florida School for the Deaf and the Blind, which Charles attended as a youth in 1937.

The boxed set includes the master takes of every Charles studio release for Atlantic -- 101 tunes -- plus 16 tracks that capture Charles and his octet live at the 1958 Newport Jazz Festival and a 1959 performance at Atlanta's Herndon Stadium. There are also dozens of soul-jazz tracks from albums with vibes master Milt Jackson and Charles's longtime tenor sax player, David "Fathead" Newman.

Also included is a DVD featuring a previously unreleased performance at the 1960 Newport Jazz Festival, licensed for the collection from Historic Films, and an interview with longtime Atlantic chief Ahmet Ertegun, who signed Charles.

Thirty-six previously unreleased studio "rehearsal" performances make up what many fans might consider the collection's most extraordinary material. By all rights, former Atlantic execs and producers say, the tracks should not exist.

Atlantic suffered a major vault fire in its Long Beach, N.J., warehouse Feb. 8, 1978. The blaze destroyed an estimated 5,000 reels of session tape, including outtakes from artists including Charles Mingus, Aretha Franklin and Charles. Many of the tracks were of fine quality and were not released simply because the vinyl LP format demanded shorter recordings. (The master tapes of released recordings remained in Atlantic's New York studio and were spared.)

Atlantic never issued an announcement about the fire. Sheldon Vogel, the label's former CFO, says the company collected $1 million in insurance from the destroyed tapes. Before the advent of the CD and the subsequent value derived from outtakes, Vogel says, "we were thrilled. Now, of course, that's a joke."

Even former label co-owner Jerry Wexler did not know about the fire for a year. He says he thought at the time that certain tapes were missing simply because of the disorganization of the indie label's vault.

Many of the outtakes heard on the Rhino boxed set would have been lost to the fire were it not for a reel-to-reel dub copy of two early Charles rehearsal sessions made for Wexler shortly before the fire by Atlantic producer and recording engineer Tom Dowd (who died in 2002 and was the subject of the 2003 documentary "Tom Dowd & the Language of Music").

"I kept it for years," Wexler says. "Then I made a cassette copy, and then a CD."

One rehearsal documents Ertegun in the studio with Charles, teaching him the lyrics to "The Mess Around," which he wrote to get Charles singing more rocking material -- a session reenacted in the "Ray" film.

The releases come at a time when Charles's profile remains as high as ever: His first big seller on Atlantic, "I Got a Woman," is the sample that anchors Kanye West's single "Gold Digger," which is No. 1 on the charts.