Someone asked me about yesterday's post - that the Lord of the Rings could be used as an evangelical tool. They asked me how. Well, there are many great Christian virtues displayed, and the central theme of the little one being at the heart of it all is Christ's teaching on the least being the greatest (I also see St Therese's Little Way in the adventure of the hobbits).
But there are excellent examples of how Tolkien's work can be used to reveal Catholic teaching and one concerns purgatory. It is the third volume, The Return of the King, Aragorn needs assistance and he turns to the souls of treacherous soldiers who now haunt what is called the "Paths of the Dead". These soldiers had sworn allegiance to the King of Gondor to come to assist it in war, however when the need was greatest these men fled and took refuge in the mountains, safe (or so they thought). They died, but their souls could not rest - they had sinned, they had a debt to repay for their cowardice and treachery and they could not enter into their rest until the debt was paid and atoned for.
And so Aragorn arrives, he is the true King of Gondor and holds them to their oath, they now go to the aid of Gondor and when the city is saved, they are finally released from their oath, they have repaid the debt, atoned for their treachery and they can now enter their rest. That, as you can see, is a wonderful exposition of purgatory, it is the place where we repay the debt our "treachery" (sin) to the King (God) has caused. And so the discussion can begin!