Book shelf? ...what book shelf?

Step 12 Secure the covers

Now replace the bungee cords or twine, used to temporarily hold the covers closed, with clear monofilliment fish line.

I've had several books held to a wall and to a door for the past 8 months using this mounting technique. With all the abuse an occupied bedroom door can give, all that has ever been needed is a slight tilt adjustment.

You can use smaller hooks and monofilliment fish line to replace the aluminum wire hanger rod for lighter books and paperbacks.