Roll Over, Eric Clapton. And Tell Stevie Ray the News.

It's official -- the blues is in again, if indeed it ever was out. Following the release of its epic DVD How the West Was Won, blues-rock icon Led Zeppelin is hotter than it's been since the 1980 day that John Bonham swilled enough vodka to poison a platoon of elite Russian commandos. Annie Leibovitz's coffee-table music book, liberally salted with blues pics snapped in and around Mississippi jukes, is due out soon. PBS gave over a whole week to Martin Scorsese and his hand-picked dream team of directors. The White Stripes hobnob with the glitterati in Switzerland. Eighties college rock icon Paul Westerberg has succumbed, too -- he's now recording the stuff under the nom de blues Grandpaboy -- and so has '90s college rock icon Doug Martsch.

And today there's a whole battleship-load of hip and young blues-based bands, two of which -- the excellent Black Keys and the so-so 20 Miles, which is led by Jon Spencer Blues Explosion guitarist Judah Bauer -- will be in town in the next few days. A third -- the blistering Boston-based female guitar/drums duo Mr. Airplane Man -- plays October 22, so if you're getting this early you'll have a chance to see two of the best of these bands inside of a week.

Others of this ilk -- most of whom owe a tremendous debt to Jon Spencer, the father of post-punk blues and a guy whose contribution to the continued survival of the genre as a living, breathing thing is enormous -- include Bob Log III, the Immortal Lee County Killers, Pearlene, Bantam Rooster and many others. Meanwhile, the recordings recently released on the Oxford, Mississippi, label Fat Possum have galvanized musicians such as James Mathus & His Knockdown Society and the North Mississippi All-Stars.

No doubt many blues purists would likely despise the Spencer-spawned, punk-fueled groups. By now, there's a lot of mud for a blues fuddy-duddy to get stuck in; today, a blues purist could be anyone from somebody who believes it's all been downhill since the day Charley Patton died to someone who regards Eric Clapton as a true keeper of the flame. Locally, acoustic guitarist Harlem Slim would fall into the former camp, and KPFT DJs Smokin' Joe Montes and the Blues Hound would be in the latter, with most of the city's legions of blues bar bands falling somewhere in between.

The Black Keys' Dan Auerbach, for one, is no purist. "The whole genre has been bastardized," he complained to an Australian paper this summer, "and turned into such a foul thing that I don't want to be part of a blues scene because of the bar-band garbage, all the bad clichés and beer-commercial things."

Mr. Airplane Man drummer Tara McManus agrees. "It's gotten to the same point with us!" she says excitedly over the phone from a tour stop in Los Angeles. "We had to take a break because in Boston we were getting known as like 'the best blues band in Boston' and we were like no, we're not a blues band! Please don't call us that! Then, the only people that wanted to give us gigs were like the House of Blues, and we would be on bills with these really wretched, wretched blues bands that played this generic, corny, uncreative, awful crap. It's so predictable and so standardized and so lame, and everybody just eats it up. They're like, 'Whoo! The blooze! Yeah! Sing the blooze!' We had to lay low for a while to get that stigma off of us."

We get the picture, but to call a band that covers Mississippi Fred McDowell, Howlin' Wolf and "Jesus on the Mainline" anything other than blues would not be right. The genre needs a name -- call it blues explosion or maybe post-punk blues, 'cause it is the blues, but, as Fat Possum label head Matthew Johnson once said of his label's products, it sure "ain't the same ol' blues crap."

What sets the music of the Black Keys and Mr. Airplane Man apart from any given blues band at any given roadhouse on any given Saturday night is the fact that Iggy Pop lurks more prominently in their pedigree than does Eric Clapton, and also, to hear them, you'd think there was no such thing as a "blues guitar slinger." And unlike most of the generic blues bands, these kids have taken the time and trouble to listen to the rootsy stuff on labels like Arhoolie, Yazoo and Folkways -- their chain of influence doesn't begin with Freddy King, Jimi Hendrix's "Red House" or the Allman Brothers' cover of "Stormy Monday." And as for the likes of Mathus and the All-Stars, they're based more on North Mississippi hypno-blues as performed by Junior Kimbrough and R.L. Burnside than the same-ol', same-ol' ba-bump ba-shwap from Chicago and the Delta.