: Hmmm, I actually get the impression that Tolkien himself wasn't sure of the power of the Rings, or at least modified this in the course of time. In The Hobbit, the One Ring appears to give only the power of invisibility. It probably has other powers, but no clue as to what these are is given.

Bilbo is not a very powerful person. He does not know how to use its other powers. In a sense he is consumed by its powers when he first puts it on, as was Smeagol and, later, Frodo and Sam; hence they disappear (into the "wraith world" which is really the spiritual world).

:In LotR, however, the aspects of greater awareness/ sharpened senses, tendency to greed and evil, desire to keep posession and ability to see into the wraith world are added. These effects are obviously in line with Sauron's ultimate desire to enslave the ring bearers.

Again, it has other powers, including the power of command. If one is personally powerful enough, one can command individuals and even whole armies by willpower.

:However, it is not clear why the bearer should become invisible. Is this just a bait to make people use the Rings in the first place?

My theory is that it only turned the weaker bearers invisible; and this only because it was the ruling ring and so powerful. People who had enough power to master the ring would not (or could choose to not) become invisible. They may be able even to choose a form that the visible world would see.

:If it did not affect the dwarves, why did they accept the rings. If it did, why didn't they use this feature to greater effect in their war against Sauron?

The rings did affect them. They were victorious in wars and prolific in gathering wealth. They became greedy and quarrelsome as well, which is why they weren't very successful against Sauron (being disunited in fighting him). Also, while Sauron wore the One, all their plans would be exposed to him.

:Also, why did Gollum not become permanently invisible?

This is explained in the text. He didn't use it all that often under the mountains. So he was slow to succumb to its effects. If he had worn it more, no doubt he would have become a wraith and brought the One right to Sauron (against Gollum's will of course, but he wouldn't have had a say in the matter). Even not as a wraith, he was still called to Mordor.

:What did Sauron do with he dwarven rings he captured? Did he give them to anyone else?

He tried to give them to the dwarves, particularly the dwarves of Durin's clan. I'm not sure he had time to distribute them though. Sauron's messenger offered Dain all three of the remaining rings. So we can assume that at that point (by the time of the Council of Elrond), he still hadn't given them away. I doubt he was able to find any dwarves receptive to his offers (since we don't find any dwarves on Sauron's side in the war of the ring).

What did he do with the Nazgul rings? He could have used these to make a second set of Nazgul?

He kept them. Safe. If Sauron had tried to make a second set of Nazgul, no doubt the nazgul would have found out. That would have pissed them off to no end. Sauron then probably would have been dealing with an insurrection. Instead of being his most faithful servants, the nazgul would most likely have become his most bitter enemies (not that they would have united with the west).

: Questions, questions, questions. I suppose we can only speculate and will never know for sure, or does anybody know?

What do you think? The invisibility stuff is tricky. But I think I have it. And in any case, I think Tolkien leaves a lot of the questions about how the rings work as mysteries, because they would not have been known to even the wisest of the wise (save maybe Saruman, and he wouldn't have told anyone even what limited knowledge he had obtained) by the war of the ring. The rings work. And nobody knew how or why anymore. A truly wonderful detail of Tolkien's.

Cheers.

Dave C-Q