Hi Chook,
I'm busy reading a book called "Cuban Fire - the story of salsa and latin jazz" which tells where the music came from. It focusses on the music, not the dance, thought.
A similar book titled "Cuban Music" explains the African origins of the music very well in the first chapters, and the progression of instruments used also very well, but again it looks at the music, not the dance as such.
I would love to get a similar type of book that focusses on the dance patricularly...