Christopher Tolkien once wrote: "But it seems to me now, many years later, to
have been an excessive tampering with my father’s actual thought and intention:
thus raising the question, whether the attempt to make a ‘unified’ Silmarillion
should have been embarked on."
To use one notorious example, many people "know" from reading the Silmarillion
that Orcs began as Elves, twisted and tormented by the Dark Lord. In fact, JRRT
seems never to have come up with a satisfying explanation of where Orcs came
from. The Elvish origin was one of many he considered.
Elsewhere CT reprints a marginal note indicating that Orcs originated as Men,
and says this was his father's "last word" on the subject, but all we can know
for sure is that it represented his thought at the moment he wrote it. Perhaps
he would have revised it again if he had the chance.
In my humble opinion, all we can really "know" about Middle-earth itself is
contained in "The Hobbit" and "The Lord of the Rings", although the other books
can be entertaining in their own right and interesting in as far as they shed
light on JRRT's thought processes and the evolution of his
work.
(Insert wildly creative footer here.)
