When you get a CD in the mail from the great producer Jerry Wexler, you pay attention to it. Especially when a note enclosed with the CD reads, "This is the best thing I've heard in the past year."

In his long and distinguished career, Wexler has worked with artists including Willie Nelson, Aretha Franklin, the Allman Brothers, Wilson Pickett, Bob Dylan, Dusty Springfield, Ray Charles, Dire Straits and Etta James. So you pay attention when Wexler speaks. He's retired now in Florida, but his ears and his mind are as sharp as ever.

The CD he sent me is Live From Cell Block D by Tracy Nelson.

Willie Nelson, who is no relation, wrote the liner notes, calling her a "vocal icon." Willie and Tracy were nominated for a Grammy in 1974 for their duet on "After the Fire Is Gone" (with Linda Ronstadt singing harmony).

Tracy has had an uneven career but produced a series of by and large excellent albums -- none of which truly capture the majesty and power of Tracy Nelson onstage. The woman doesn't need a microphone or amplification. This, which I think is her 21st album, is her first live project and comes very close to approximating one of her live shows. It was recorded just before Christmas of 2002 on Cell Block D at the West Tennessee Detention Center in Mason, Tenn. Nelson performed and recorded two shows. The first was for male inmates and the second for the women prisoners. The prison authorities, not too surprisingly, would not allow a mixed audience.

In her liner notes, Tracy writes, "I was admittedly a little insecure about how we could come across: Would we seem like dilettantes in the profound reality of a prison setting? As it turned out, both audiences responded beyond our wildest expectations. Two things in particular surprised and gratified me. In the first show for the men, I could hear reacting to the lines about finding a spot 'with peace that surrounds me' and 'a place to forget all my regrets and feel free at all times' losing 'those Tennessee blues.' I can only imagine their palpable response came from where and how they found themselves. In the second show for the women, I was stunned to see a young black woman in the second row singing along with all the lyrics of 'Walkin' After Midnight.' It reinforced my belief that Patsy Cline is god."

Highlights abound here -- hell, the whole album is one long highlight. But she takes Lyle Lovett's "God Will" and transforms it into one of the most gorgeous, soaring, soulful gospel hymns you will ever hear. Only Tracy Nelson (or George Jones) can turn the word "God" into five or six drawn-out syllables. The raucous "Got a New Truck" is a rocking country music soundtrack in search of a TV show. Bobby Charles' exquisite composition "Tennessee Blues" is one lovely anthem. She takes "After the Fire Is Gone" from being a somber, reflective duet (as Loretta Lynn and Conway Twitty first sang it) into a defiant honky-tonk torch song. And her signature blues song "Down So Low" is as powerful as ever and remains one of the most affecting laments ever.

She has one of the most marvelous voices you will ever experience, one that's equally home in country, blues or R&B. She can go from shouting down the trees to a velvety caress of a whisper and fully engage you all the while. She has never really had the guidance, or perhaps the ambition and drive, to relentlessly pursue stardom. But no one sings the way Tracy Nelson can. I highly recommend Live From Cell Block D. It's far and away the best thing I've heard in the past year, too.