by Alex Henderson   In 1984, a 45-year-old Tina Turner made one of the most amazing comebacks in the history of American popular music. A few years earlier, it was hard to imagine the veteran soul/rock belter reinventing herself and returning to the top of the pop charts, but she did exactly that with the outstanding Private Dancer. And Turner did so without sacrificing her musical integrity. To be sure, this pop/rock/R&B pearl is decidedly slicker than such raw, earthy, hard-edged Ike & Tina classics as "Proud Mary," "Sexy Ida," and "I Wanna Take You Higher." But she still has a tough, throaty, passionate delivery that serves her beautifully on everything from the melancholy, reggae-influenced "What's Love Got to Do With It" to the gutsy "Better Be Good to Me" to heartfelt remakes of the Beatles' "Help," Al Green's "Let's Stay Together," and David Bowie's "1984." A reflection on the emptiness of a stripper's life, the dusky title song is as poignant as it is depressing. Without question, this was Turner's finest hour as a solo artist.