The power of music is one of the great unknowns in the human saga. For reasons we don’t quite understand (yet) its vibrations can lift us to great heights, drop us down into deep depression, liberate us, make us joyous, help us grieve, and so much more. Stephen Stills, Graham Nash and David Crosby perform at the Amphitheater at the Wharf in Orange Beach in 2008. (Press-Register, G.M. Andrews)