I have that book, and I think it is a good one. It is by a psychologist, and, as Orange Blossom said, she explains what dissociation symptoms are, ahd how to recognize them. It is about more than DID. There are screening questionnaires in the book to see which symptoms you might have (like the one on the author's website, for Depersonalization, on which I just scored 56). One criticism of the book is that it tends to read like an infomercial for the diagnostic test that the author created. That is a bit irritating, but it is still a great book.