Mortality and immortality underlie the “emotional truth” (95) of Tolkien’s backstory, a truth which draws us as readers into a world in which longing and loss, death and deathlessness, are the foundation of a sub-created world that we as readers desire. The fantasy frame in Tolkien’s legendarium is extremely deep, and has been highly influential on other creators.
Chandler, Wayne A. and Fry, Carrol L.
"Tolkien's Allusive Backstory: Immortality and Belief in the Fantasy Frame,"
Mythlore: A Journal of J.R.R. Tolkien, C.S. Lewis, Charles Williams, and Mythopoeic Literature: Vol. 35
, Article 7.
Available at: http://dc.swosu.edu/mythlore/vol35/iss2/7