For Guralnick, the naked emotion of the blues imposes a duty on the listener. "People have to open themselves up to it," he says. "You can't impose the conditions of what you're used to on the blues, just like you can't on poetry or Shakespeare. If you come in with an open mind and heart, you'll never forget it."

With its pantheon of storied names - including Lead Belly, Lightnin' Hopkins, Willie Dixon, Blind Lemon Jefferson, J.B. Lenoir, Skip James, and John Lee Hooker - nobody would deny that the blues has a proud history. But what of its future in a forward-march, youth-intoxicated country bursting with entertainment options?

In the magazines, books, and websites devoted to the blues, it's easy to hear notes of concern over the genre's health and survival. Because blues records rarely sell anything like the numbers seen for rock, rap, and country, even the legendary B.B. King, 77 years old and diabetic, spends about 200 days a year on the road. "If I don't keep doing it, keep going, they'll forget me," King told The New York Times. It's not a worry we tend to hear from, say, Mick Jagger, Celine Dion, or Garth Brooks.

The Memphis-based Blues Foundation sponsors a yearly International Blues Challenge, looking for promising young players who will "keep the blues alive." At the same time, the Foundation's yearly W.C. Handy Awards often go to veteran performers like King, Clarence "Gatemouth" Brown (born in 1924), Buddy Guy (1936), John Hammond (1942), Marcia Ball (1949), and Keb' Mo' (1951). The 2002 award for Best New Artist went to Otis Taylor, who was 53 when he picked up the Handy.