Charles Gaines, the author who helped bring bodybuilding into the mainstream with "Pumping Iron," has died at 84. His daughter Greta confirmed his passing on Tuesday. Gaines collaborated with George Butler on the book and documentary "Pumping Iron," which introduced Arnold Schwarzenegger to the world. Initially, Gaines didn't expect the book to interest many outside bodybuilding. Schwarzenegger, who won multiple Mr. Olympia titles, later became a movie star and governor of California. Gaines, who began lifting weights at 16, also wrote novels like "Stay Hungry." Schwarzenegger praised Gaines for his adventurous spirit and influence.