I've been looking for a VERY basic book on music and spent almost a hour going through the shelves of my favorite book store where I discovered a book titled "Blueprints for Muscial Understanding" by Saul Feinberg, that I bought for two dollars, American.
So far it has given me a much undestanding of the whys and wherefores of music as well as the construction of scores.
If you havenT checked out such places, I highly recomend it as ime well spent.
Bike