An enterprising user at DIY web site Instructables explains how to make a book pillow that keeps your book open for hands-free reading.
You'll need to be willing to get your hands dirty with a little needle- and thread-work, but the post lays out every step with plenty of detail. The author points out that, once finished, you can add a bookmark at the top of the pillow (pictured) or sew a metal clip to the top to keep your more stubborn books open to the appropriate page. Crafty!
Hands-free book pillow [Instructables]