There is of course a clash between ‘literary’ technique, and the fascination of elaborating in detail an imaginary mythical Age (mythical, not allegorical: my mind does not work allegorically). As a story, I think it is good that there should be a lot of things unexplained (especially if an explanation actually exists); and I have perhaps from this point of view erred in trying to explain too much, and give too much past history. Many readers have, for instance, rather stuck at the Council of Elrond. And even in a mythical Age there must be some enigmas, as there always are. Tom Bombadil is one (intentionally).

J.R.R. Tolkien (1892-1973) English writer, fabulist, philologist, academic [John Ronald Reuel Tolkien]

Letter to Naomi Mitchison (1954-04-25)
    (Source)

Letter 144 in Humphrey Carpenter, ed., The Letters of J.R.R. Tolkien (1981).