[Groin Redbeard]

Great literature according to Aristotle, did not explicitly draw attention to the themes that one sought to explain. Rather, they were subtley concealed within the text so that the reader, through reason, could draw them out.
Such themes abound in LOTR. Simple examples include the character of Gandalf. He is a pure spiritual being - an Istari - who choses to become incarnate in order to combat evil. If this does not in part reflect a Christocentric theme what does. Also, in his fight with the Balrog in Moria, Gandalf dies, but returns to earth, no longer as Gandalf the Grey, but rather Gandalf the White. His powers are increased and all are awed in the revelation of his glory in Fangorn forest. Can one not envision the parallel to the glorified Christ after the Resurrection.

Then there is the Lembas - the Elf bread - which sustains the members of the Fellowship through their journeys. What more specific example of the Catholic view of the Eucharist does one need.
One final example is the date chosen for the destruction of the Ring - March 25th. In the Catholic liturgical calendar, this is the date of the feast of the Incarnation - the date when Christ became incarnate in the womb of Mary and the saga of the Redemption of Man began. What other event can one identify more closely with the Christian understanding of the destruction of evil than this.

But the overall key to Tolkein's LOTR is not that it is a specifically Christian work, but rather a work of myth that is infused with a Christian spirit. Let me explain another way. We each have are everyday activities. We go to work, take care of our families and tend to social duties. These are rather mundane secualar activities for the most part and seem far removed from God and Church. But that is the drama of the Christian life - to take the ordinary, and transform it into a work done for God. Much as Christ lived an ordinary life as son and carpenter, transforming this life into the extraordinary, so Tolkein harkens us to this image. The image that all human activities, from the drama of Helm's Deep, to the simple daily lives of hobbits, can be transformed into something truly dramatic in Christ. This is the meaning of a Sanctifying Myth and also the meaning of our lives as Christians (Catholics and Protestants)- to sanctify the ordinary.