Four roller ball switches and a 3d printed housing (file available here) can be used to "know" that the book has been picked up.

The housing provides a slight downward tilt so that the roller ball switches are all reset when the book is resting on a flat surface. The short wire (brass color) should face outward--when the switch is tilted toward the brass wire end, electrical connection is made.

I use wire wrap wire to connect switches together. The four switches are wired in parallel.