Here's a short list of titles on or related to the subject plus info on an upcoming library-sponsored workshop:
Altered Art : Techniques for Creating Altered Books, Boxes, Cards & More by Terry Taylor
Altered Books, Collaborative Journals, and Other Adventures in Bookmaking by Holly Harrison
New Directions in Altered Books by Gabe Cyr
Artist Trading Card Workshop : Create Collect Swap by Bernie Berlin
Print Workshop : Hand-Printing Techniques and Truly Original Projects by Christine Schmidt
Additional 'How-to' Titles
If you and your kids are interested in engineering, you might like to experiment with pop-up construction projects. More traditional books about bookbinding will also be helpful to undertaking an altered book project.