P: Book Module – Unfinished book vanishes

I’m creating my first Blurb book inside of Lightroom 4. There are some 175 images in my collection/filmstrip. I was about 80% complete with the book, when I selected an image to go into the Development Module for adjustments. When done I returned to the Book Module. But the book was gone! The filmstrip at the bottom of the page is there indicating images are in the book, but the book itself is empty with only a cover and two blank pages. If I add an already “used” image, the filmstrip counter goes from 1 to 2.

Trying to fix this problem, I backed up and optimized my catalog. But upon restarting Lightroom no change... and no book!

Any suggestions as how to get my book back? Or do I have to start over!