In Tolkien's Words: Lord of the Rings and Christianity

J.R.R. Tolkien was not fond of potential biographical accounts concerning his life and experience, or literary critiques based on an author's personality, family life, place of birth and so forth. The same was true for his friend and colleague, C.S. Lewis. Together, these men shared the great intellectual and literary insight that the best way to get to know an author is not primarily by reading his or her biographical works - those of a secondary nature -but through the primary sources of the written by the author. It's a good practice in history, literary analysis, and theology, just to name a few disciplines: what does the primary source say? Deal with the primary text first before moving on to secondary sources, biographies, commentaries, and the like. For these two literary giants the key to their literary insights was to pick up a book and listen to the author's own words. So, the best biography available on Lewis or Tolkien their respective literary output. (Of course, neither men entirely dismissed biography and neither should those who read, mark, and study their work. After all, there are several excellent biographical works written about Lewis and Tolkien.) One of the greatest biographies on Tolkien you can read is Lord of the Rings and The Hobbit.

I've often said that the reader who wants to know Tolkien should read two things: 1) his letters and 2) his essay On Fairy Stories. In reading Tolkien's letters I've discovered a deep mine, rich with veins, pockets, and nuggets of literary wisdom and insight into his sub-created world of middle-earth, as well as his own thinking. From time to time it is my hope to post more of these treasures here for others to read and enjoy as I have. So here's Tolkien in his own words on LOTR and Christianity

In a letter dated December 2, 1953 Tolkien replies to a close friend of the Tolkien family, Father Robert  Murray, after he had read typescripts and proofs of The Lord of the Rings and had inquired about Galadriel paralleling the Virgin Mary. Tolkien affirms this and goes on to make one of his more remarkably lucid statements on the presence of Christian symbolism (not allegory) in his writings.

I know exactly what you mean by the order of Grace; and of course your reference to Our Lady, upon which all my perception of beauty both in majesty and simplicity is founded. The Lord of the Rings is of course a fundamentally religious and Catholic work; unconsciously so at first, but consciously in the revision. That is why I have not put in, or have cut out, practically all references to anything like 'religion', to cults or practices, in the imaginary world. For the religious element is absorbed into the story and the symbolism. However, that is clumsily put, and sounds more self-important than I feel. For as a matter of fact, I have consciously planned very little; and should chiefly be grateful for having been brought up (since I was eight) in a Faith that has nourished me and taught all the little that I know; and that I owe to my mother, who clung to her conversion and died young, largely through the hardships of poverty resulting from it.

J.R.R. Tolkien, Letters, ed. Humphrey Carpenter, Letter 142, p. 172.