It is interesting because the denouement, which wraps up everything in this story, actually sets the stage for the beginning of "The Lion, the Witch, and the Wardrobe." "The Magician's Nephew" ends with Digory saving his mother by bringing her an apple from Narnia, which he managed to do by resisting the temptation to eat it himself. Afterward he takes the apple core and buries it in the backyard. It grows into a magnificent tree with the best apples anywhere in England. Later, when the tree is destroyed by a storm, Digory has the wood made into a wardrobe, thus setting the stage for what many consider to be the first book in the series.
Check the links below for information on both denouement and the story itself. Good luck!
In addition to the wonderful tie-in of the apple leading to the wardrobe, there are a few other "explanations" for objects/situations in the other Narnia books.
For example, when Jadis followed Diggory and Polly to the new Narnia, Jadis had grabbed the arm of a lamp post from England, and carried it with her. When Aslan approached, singing Narnia into existence, she threw it at his head, but it merely glanced off and sank into the earth. It then functioned much like a seed, growing a new lamp post which became the meeting place for Lucy and Sir Tumnus the Fawn in "The Lion, the Witch, and the Wardrobe."
Also, Diggory buries the rings (made by Uncle Andrew to take them to the Wood Between the Worlds) in a circle around the base of the apple tree in England. In the last book, "The Last Battle," the Pevensies dig up the rings in order to get back to Narnia after seeing a vision during a dinner together with some of their oldest friends (like Diggory, who actually becomes the Professor who owns the house in "The Lion, the Witch, and the Wardrobe").
Basically, the denouement of "The Magician's Nephew" explains a good many things about "The Lion, the Witch, and the Wardrobe," as well as tying into other books in the series.