We're getting around to the realization that the 1990s saw the most innovation in popular music since the '60s — and that realization encompasses even staid subgenres such as vocal jazz, which most aficionados believe is just fine as long as it sticks to the pre-'60s canon. Cassandra Wilson probably did more to advance vocal jazz in the '90s than any other singer, and she did it as she turned 40, after years of flailing around for a distinctive style.

Her 1993 album "Blue Light 'Til Dawn" remains a watershed record; an idiosyncratic take on acoustic blues, the bedrock of jazz. However, it was the followup, 1996's "New Moon Daughter," that shook things up. Reinterpreting rock and pop standards as well as some classics that normally resist reinterpretation (such as Billie Holiday's "Strange Fruit"), Wilson raised eyebrows with an art-song style that recalled Nina Simone but without Simone's earthiness. Sometimes she got carried away attempting to prove that not only is every piece of music worthy of attention, but that she could single-handedly make it so. But trying to make the Monkees' "Last Train to Clarksville" something profound seemed pointless.

Since then, she has branched out even more, and in the process gradually returned to conventional jazz. She toured with Wynton Marsalis, released a fine tribute to Miles Davis called "Traveling Miles," and on "Belly of the Sun" revisited soul and pop tunes in a way that sounded less contrived than "New Moon Daughter." She's also developed as a composer and experimented with hip-hop. Her new album, "Loverly," brings her full circle, back to the canon, and it's one of the finest collections of jazz and blues vocal standards released this decade. But don't call it nostalgic. To Cassandra Wilson, even old songs are new territory.