I don't know if this cel actually matches the 
explanation of being a book cel, but I think it 
is one.

I think it because the background is made out of 
two layers. One background layer is the wall 
right from Scarlet's face, above it is another 
background layer showing the edge left from her 
face. The cel is above those two layers but you 
could also have placed it between the two 
background layers.

Could someone tell me if this really is a book 
cel?

Thanks!
Dennis