The Magician's Nephew

Polly and Digory meet and become friends, and Digory's crazy magician uncle captures the two children and sends them off to another world with some magic rings. Digory and Polly meet an evil witch who tags along with them and they all end up at the very beginnings of Narnia.

This is probably my third favorite Narnia book after The Lion, the Witch, and the Wardrobe and The Voyage of the Dawn Treader. I enjoyed seeing how Narnia started and I also loved the chapter where the witch follows the children to our planet.