Can anyone tell me if the cover of the books is premade fondant and assembled on the cake?
Contact Sarsi here on cc. See her gallery. She has a great tutorial on books.
The bottom cover is just thin strips cut and place around the "pages". The top and side binding is measured and cut then applied over your iced cake. Allow 1/4" - 1/2" on all edges to allow for covering the thickness of your "pages" that go on after the top cover.
Sarsi can provide instruction if this quick snippet isn't enough.