The 12th Ponderosa Stomp features a massive musical lineup encompassing genuine instigators of rock ’n’ roll, soul, blues and swamp pop. The festival runs Thursday through Saturday .

Stomp organizers have packed their Friday and Saturday concert schedule at Rock ’n’ Bowl with under-the-radar yet indispensable talent. In the Stomp producers’ words, they’re presenting “the rawest, deepest stuff out there, simmering under the surface, waiting to be rediscovered before it’s too late.”

Night one includes classic soul singers Mable John, Betty Harris and Brenda Holloway; Freddy “Boom Boom” Cannon (“Tallahasee Lassie,” “Palisades Park”); swamp pop singers Tommy McLain (“Sweet Dreams”) and Rod Bernard (“This Should Go On Forever”); “Eve of Destruction” and “Secret Agent Man” composer P.F. Sloan; and Sun Records drummer J.M. Van Eaton (“Whole Lotta Shakin’ Going On” and “Great Balls Of Fire”).

Night two of the Stomp concerts includes New Orleans soul singers Irma Thomas and Tony Owens; singer-guitarist Barbara Lynn (“You’ll Lose a Good Thing”); the Sir Douglas Quintet’s Augie Meyers (“She’s About a Mover,” “Mendicino”); and Lynn August, zydeco performer and keyboardist for Esquerita, a rock ’n’ roll pioneer who influenced Little Richard.

The festival’s two-day history music conference is Thursday and Friday . Music journalists and historians, including Ann Powers, Robert Gordon, Ed Ward and John Broven, will interview many of the 2015 performers.