Throwback Pics: Behind the Scenes at the Academy of Country Music Awards

A new book, This Is Country, offers an exclusive peek at 50 years of the show's most memorable moments

WALK THIS WAY

"I still can't believe we pulled that performance off," Carrie Underwood says of her 2011 surprise duet with rocker Steven Tyler. "I had so much fun up there with Steven, and even now, I will pull up that YouTube video to watch again."