i'm teaching a first-year seminar on 'american popular musics'. it is a great time to teach a course like this because everygoddamthing is on youtube. it's amazing the footage you can have instant access to through a casual search. so anyway, i guess i've been building a sketch of the history through playlists.
blues (blues harp) (blues piano) (blues guitar)
swing; (i had a pre-swing jazz list; seem to have misplaced it); the idea of improvisation
early country; bluegrass; 60s country; 70s/80s/90s country; recent country
more to come in rock and hip hop.