I said this once in another thread on this forum to explain as briefly as possible what it feels like to be an NPD..based on my experience being raised by one, and having loved two others. It met with a positive response from two people I highly respect in this forum.

"Who am I? I'm the mirror. I have always been. مرآة Mirat...the mirror.

The problem being, of course, that I am reflective...only. Within the mirror is glass...fragile, and sharp."

If the book is about NPD, I'd guess this would do for an explanation of title.