[rfreedom4u]

Why is it that anyone who puts on the ring turns invisible EXCEPT for Sauron?

[MortMan]

Sauron was fully evil - he existed in both the shadow world that Bilbo disappears into and in the “real world”.

That’s how I would answer the question, although I admit I have never really thought too much about that before! ;-P

[Mr Rogers]

"Why is it that anyone who puts on the ring turns invisible EXCEPT for Sauron?"

Because the ring WAS Sauron. He poured himself into it. In a sense, the ring was possessed by Sauron. When he had it, he was still fully himself. When someone else tried to use it, then Sauron-in-the-ring would twist and overpower their nature. And as long as the ring existed, part of Sauron was still alive and could recover.

[Kartographer]

"Why is it that anyone who puts on the ring turns invisible EXCEPT for Sauron?"

Hmm....Could it be it is his ring? He created it and willed some of his power into it. It's lost and therefore his lost of power is what weakened him and its destruction is what destroys him in the end.

[Sloth]

Why is it that anyone who puts on the ring turns invisible EXCEPT for Sauron?

Sauron can actually control the ring, rather than just being affected by it.

By the way, he was not the only one. In the books, Tom Bombadil put the ring on without disappearing.