The chronicle of the legendary Alabama studio brings to life decades of rock, blues, and R&B history from The Rolling Stones to The Black Keys.   An estimated four hundred gold records have been recorded in the Muscle Shoals area. Many of those are thanks to Muscle Shoals Sound Studio and the session musicians known as the Muscle Shoals Rhythm Section--also dubbed "the Swampers." Some of the greatest names in rock, R&B and blues laid tracks in the original, iconic concrete-block building, including Cher, Lynyrd Skynyrd, and scores of others.   The National Register of Historic Places now recognizes that building, where Lynyrd Skynyrd recorded the original version of "Free Bird" and the Rolling Stones wrote "Brown Sugar" and "Wild Horses." By combing through decades of articles and music reviews related to Muscle Shoals Sound, music writer Carla Jean Whitley reconstructs the fascinating history of how the Alabama studio created a sound that reverberates across generations.