The full title of the book is "The Crafting of Narnia: The Art, Creatures, and Weapons From Weta Workshop".
Weta Workshop is the Academy-Award winning special effects house that has also created the world for Lord of the Rings and King Kong. That's Middle-Earth and Skull Island. I've a book review on the World of Kong on my blog also. That book is very good.
Many books have been released in companion to the Narnia movies. If you're looking for the art book, this is the one.
This book contains the concept art done in preparation for the two movies, The Chronicles of Narnia: The Lion, the Witch and the Wardrobe, and The Chronicles of Narnia: Prince Caspian.
There are detailed photography, never before seen drawings, sculptures, props, minatures and paintings. All these are created for the characters, weapons, armour and the set. Movie stills are few.
Particularly interesting are the character designs because they show the evolution. Several designs are shown for each character, including sculptures. Weapons and armour designs are also heavily featured. The designs are intricate and many high resolution photos are provided of the actual weapons used on set -- the swords, shields, axes and the like. There are few drawings for the landscapes.