This chapter was formerly called "The Two Faces Of Music",
because there was, at first, only one dichotomy,
which developed into a whole series,
each one within the others like Russian dolls.

Do not be unduly surprised that we start with something
as general and esoteric as the Oriental YING-YANG,
to end up with very specific and technical musical precisions.
It was no easy task to establish the content of each page.
Feel free to browse.