Crosby Stills Nash & Young

Defining folk rock is a paradoxical task, to say the least.

He wrote "I Watched It All Come Down" to express his regret they didn't do more together.

"His legacy will continue to live on through his legendary music," Crosby's wife said in a statement.

Singer-songwriter says both groups "started drifting away" from the values he believed in.

Songwriter previews his book 'A Life in Focus' and teases upcoming albums.