The Amber Spyglass
by Philip Pullman
Pullman does a fascinating and complex job of showing his characters grow up without making a fuss or calling attention. In the first book, Lyra has plenty of energy and will, but it's all about hiding from grownups or manipulating them, or running away. She's a child. In The Subtle Knife, she's on her own, alone with Will and her guiding spirit and with a mission she doesn't understand but knows is right. And in The Amber Spyglass, she is in control and in charge and she knows what must be done; she is a woman long before she walks into that murmurous golden glade.