This book continues the delightful pattern of the series of showing us how these characters interact, where their biases and abilities and losses conflict and complement. Each character has their own shifting motivations, always similar enough to keep them moving forward together on their quest... until one or more does not go forward anymore. Since the doors themselves respond to the children's certainty, the plot is driven by an intersection of the characters and the universe. 

Let's talk about the dinosaurs. Delightful, no notes. Feathered, brightly-colored, and fluffy, plus viciously terrifying.