[Formendacil]

Just a couple of reference points:

1) You are quite correct, Master Fordhim, in suggesting that Elves do not make regular use of books. Tolkien confirms this in one of the writings published in one of the later History of Middle-Earth volumes. I believe it is in a discourse that had Pengolodh telling Aelfwine that in the First Age, much knowledge was lost to the Elves, because they did not have their lore in written form, for the most part, since the scholars retained it all in their minds, and so much knowledge was lost thanks to Morgoth. However, from the wording, I seem to recall that it could be implied that Elves had since taken to greater use of books, due in large part to disasters such as that.

2) This is just conjecture on my part, but Elrond's library may well be derived in large part from the archives of the Kingdom of Arnor, since it is said, in the Akallabeth, I believe, that such lore concerning Numenor was preserved mainly in Gondor, namely in Minas Tirith, and in Imladris, where the remnants of knowledge in the north kingdom were deposited. That doesn't conclusively make Elrond's library Mannish in origin, but it DOES support the idea that it isn't really an Elvish idea.