I have a question that has been bugging me since I first read the Silmarillion. A silly question perhaps, but it has bothered me nonetheless.

In the story of Beren and Luthien, Finrod and Beren come to Sauron. Felagund and Sauron strove with songs of power. "Then Sauron stripped from them their disguise...But though their kinds were revealed, Sauron could not discover their names or their purposes." The book states that Sauron attempted to keep Finrod to the last, because he "deemed that in him lay the secret of their errand."

My question. How did Sauron not know who Finrod was? Wouldn't he have known Finrod in Valinor...or was Sauron not in Valinor? What am I missing here? Any explanation on this would be greatly appreciated.

Ahhh...I see.  It is funny what a difference those few words make.  It does seem nitpicking, but it has always bothered me.  I knew there was an answer and figured you were the person who had the answer to it.  Thank you so much!

I'm not sure that Sauron was in Valinor. In fact Melkor was chained before the Elves were summoned to Aman. Feanor was not yet born and he would be Finrod's uncle and the eldest of Finwe's children. As it is, "Sauron they did not find." [Sil, ch. 3] Therefore, as I see it, Sauron was in hiding before the Elves even got to Valinor and Finrod was born in Valinor, Sauron was still in M-E. So no, Sauron would not have known Finrod in Valinor.