P: Make it possible to move pages between books

For 15 years I've made a book with my best pictures and pictures telling stories of main events of the year and send it to family and friends. The books are made with exactly the same design and exported as a pdf.

Now I want to make a Blurb book with all the pages from the last ten years. But I can't find a way to move pages between books – to accumulate pages from those ten books to a new one to be printed with Blurb.

I would appreciate a way to move pages between books. It's OK if I have to reformat, but texts and images should be preserved.