"This album puts a spotlight on the songs and the way that we interpret them, which hinges on the unique chemistry we've developed as a band," Haynes explains.

Shout! also put the spotlight on a variety of A-list singers besides Haynes that includes Dave Matthews, Steve Winwood, Dr. John, Toots Hibbert, Elvis Costello and Glenn Hughes, who've each recorded an alternate vocal performance of one of the first disc's 11 new compositions. So fans who purchase Shout! hear both Haynes' vocal performances with his bandmates Matt Abts, Danny Louis and Jorgen Carlsson, plus Haynes and crew instrumentally backing one guest vocalist on each of the tunes.

Dr. John, for example, growls on the alternate version of the funky "How Can You Stoop So Low" and Costello snarls out the lyrics of the post-new-waver "Funny Little Tragedy."

The notion of having guest singers was inspired by a conversation Haynes had with his friend Costello. "I called to ask him what type of vocal microphone he'd used on one of his classic albums with the Attractions," Haynes says. "Then, after writing and recording 'Funny Little Tragedy' I couldn't get his voice out of his head and began thinking about pairing other vocalists with the set's other songs."

So Haynes made of list of Shout!'s titles and his top choices for singers, and his first-draft picks agreed � a tribute to Haynes' and Gov't Mule's standing among their peers.

"No one's done this before, which is exciting," the Signature Model Les Paul Standard playing guitarist notes, "but it's even more exciting actually listening to these artists sing our songs. Their performances bring new ideas, energy and sometimes even different meanings to every number."