from pages 410-11 of THE LETTERS OF J.R.R. Tolkien (edited by H. Carter) Houghton Mifflin
17 July 1971
The 'immortals' who were permitted to leave
Middle-Earth and seek Aman - the undying lands of
Valinor and Eressea, an island assigned to the
Eldar - set sail in ships specially made and hallowed
for this voyage, and sterred due West towards the
ancient site of these lands. They only set out
after sundown; but if any keen-eyed observer
from that shore had watched one of these ships
he might have seen that it never became
hull-down but dwindled only by distance until
it vanished in the twilight: it followed the
straight road to the true West and not the
bent road of the earth's surface. As it vanished
it left the physical world. There was no return.
The Elves who took this road and those few
mortals who by special grace went with them,
had abandoned the History of the world
and could play no further part in it.
The angelic immortals (incarnate only
at their own will), the Valar or regents under God,
and others of the same order but less power
and majesty (such as Gandalf) needed no
transport, unless they for a time remained
incarnate, and they could, if allowed or commanded,
return.
As for Frodo or other mortals, they could
only dwell in Aman for a limited time - whether
brief or long. The Valar had neither the power
nor the right to confer immortality upon them.
Their sojourn was a 'purgatory', but one of peace
and healing and they would eventually pass away. . .
