The book also begins with a definition of privacy that's remarkably similar to the one I'd independently arrived at.
Westin:
Privacy is the claim of individuals, groups, or institution s to determine for temselves when, how, and to what extent information about them is communicated to others.
My own:
Privacy is the ability to define and defend boundaries on disclosure of information pertaining to oneself.
Both have the notion of limits, control, and autonomy over information. And I like to think that this suggests I'm on a productive track myself.