I used to say that The Work is a process leading to the state of nonduality as sought by students of Dzogchen Buddhism or Advaita Vedanta.
We could also say that Byron Katie is not a nondualist because she uses terms like "joy" and "happiness" to describe her existance, rather than the more advaitin terminology of "nothing" and "emptiness," thus making "nothing" into "something." ("No thing" is the optimal experience of advaita, by the way).
The trouble with the idea of nondualism is that it has to be demonstrated through language and concepts, which of course create more duality and separation.
However on a practical note, a book title like "No Identity and No Attachment to What Is Not," or "A Thousand Names for Nothing" probably wouldn't sell many copies to folks like you and me who still believe we are not awake. :0)
©2007 by Carol L. Skolnick; all rights reserved.