@Ace-Connell I do not have the Art of Frozen or Tangled yet - but they are both in my Amazon wish list! I follow a few of the visual development artists from both of those films on various social media sites and am always thrilled when they share a piece they had worked on during the production process. Now I really want to get those books asap!
Glen Keane is amazing - I am a huge fan. All of those iconic characters - Ariel, Beast, Aladdin, Rapunzel, Tarzan - the list goes on and on!
Speaking of Art of Disney books - I did just get The Art of Disney Golden Books and I love it. It does not have a lot of the research and pencil work (there is some) but it does have such incredible pieces created by some of the greats at Disney over the years. And it really brings me back to my childhood as I read those very books over and over and over again - seeing as back then you could only see the movie if it was in the theaters. So you had to rely on these books to bring the stories to life afterwards.