I recently finished rereading The Chronicles of Narnia with the final battle being The Last Battle. A good book (or series of books) is only as good as its conclusion and The Last Battle is a satisfying conclusion to the Narnia stories.
If The Magicians Nephew is the Genesis of Narnia, The Last Battle is Revelation. It tells the final story of the adventures in Narnia, tying together much that had happened in previous stories.
The story begins with an ape who manipulates a donkey into wearing a lion skin, thus pretending to be Aslan. This is used for the simple purpose of power but it quickly spirals out of control. Not only do the Calormenes get involved, but their god Tash (who seems to be some sort of demon) appears as well.
Jill and Eustace, who had been important parts of the Silver Chair, play an important role. We learn that there are actually seven friends of Narnia, including: Lord Digory, Lady Polly, High King Peter, King Edmund, Lord Eustace, Queen Lucy, and Lady Jill. The saddest part of the story is that Susan is not included, as she had stopped believing in Narnia.
This is definitely the darkest of the Narnia stories and I could see some overlaps with the tone of That Hideous Strength from C.S. Lewis’s Space Trilogy.
That is not to say that it is completely dark. The book ends on a very positive note as Aslan appears. The old Narnia is wiped away but a new Narnia, a better Narnia, a more real Narnia is created. Old friends from throught the series make their appearance. It is one of the clearest portrayals of a Christian worldview in the books.
The Last Battle is worth reading for both children and adults. In a world where people are often talking about the end, it is probably one of the better books to learn from.