[Bêthberry]

In support of earlier comments, I would suggest looking at another of Tolkien's professional essays, "On Fairy-Stories." It does not so much explain the mythology or languages which Tolkien imagined as present his defense of the importance of fantasy (faërie or the perilous realm) as something applicable and important for adults.

I would, however, wish to suggest a slight caution about both The Letters and Carpenter's Biography--and this is from the rather pedantic perspective of boring old scholarship.

Both are engaging, highly readable books and valuable. But neither is truly definitive. Both authors owe great debts to the courtesy of the Tolkien family for granting access to papers; there could well be many ways in which the family's wish, even unconsciously, to provide a particular view of the man influenced the selection of information and perspective given in the books.

For instance, Carpenter's opening chapter, "A Visit", belongs to the tradition of literary biography first established by the novelist Elizabeth Gaskell in her ground-breaking biography of Charlotte Brontë. This, in itself, is not evidence of flaw or error, but it suggests that Carpenter was writing both an interpretation of the man and of the genre.

It would, for instance, be fascinating to read all of Tolkien's letters to Edith Bratt, which are quoted only sparingly. And, as Carpenter acknowledges, much of Tolkien's correspondence still remains untraced.

These resources are, for now, preliminary studies of the man and it is wise not to view them them as carved in stone.