Missing the other half of the book cos total should be around 150pgs. My guess would be the 'pairing' pages, or the adult ver. of the images, hence @LeGenjutsu's even page numbers list. Or, they could be either rough sketch, or maybe just some write-ups.
The book has one Page illustration, and one page artist comments (both together as a double page), so there are basically one illustration every two pages. The Author Info/comments aren't included in this gallery