I think that writing a really good novelization is becoming a lost art. But Nancy Holder knows what she is doing. This is everything a good novelization should be.
The novel, obviously, follows the plot and action of the recent Wonder Women movie. The motivations and thoughts of several characters are fleshed. Importantly, there are three Amazons that Diana particularly admires - her mother, her aunt (aka her other mother), and Artmis (who is the black Amazon that Diana spars with in the movie). This is cool. I also highly enjoyed Diana's thoughts on Etta. There are some really wonderful passages, like young Diana's desire to fight peacocks. One improvement over the movie is the story of the Amazon's birth and the fight with Ares. Holder has both Antiope and HIppoytla tell Diana the story. I like Holder's staging of the story much better.
Incidentally, there was some comment about Diana's interaction when she meets Chief - the use of Blackfoot language is kept without a translation (it's easily enough to find out what is being referred to online). I really loved that touch.