In the Book Module in Lightroom 4, you can easily see what images have yet to be added to the book by selecting “Unused” from the Filter presets. You can also chose to view only the “Used” images. Note: the Filter options can be found in the lower right of the application, in the black bar, above the filmstrip.

Great filter book to read
coool. its cool
Good and useful tip. Filtering photos give a better outline of which photos I am working with.
Hello,
I am trying to create a book of my daughters wedding. The collection has about 400 images. I saved the book after I had input about 140 into the book. It will not allow me to add anymore of the remaining images into the saved book. Is there anyway that I do this without having to restart the book? Many thanks
I would post the issue to either of these forums to see if other customers are experiencing the same problem and if so, if they have found a solution.
http://forums.adobe.com/community/lightroom
http://feedback.photoshop.com/photoshop_family