Its been some time since I read FOTR and over 20 years for The Hobbit, so this may be covered but I dont remember. Why could Gandalf not recognize Bilbo's ring as the one Ring? And on a related note, why could he not sense what was happening in Mordor?

The Ring had been lost for a very long time. Also, Bilbo was already pretty secretive about it, even to Gandalf.

Mostly though, it was simple complacency. He knew there was something funny about the Ring, and just didn't think to really look into it until right after Bilbo's going away/birthday party.

As for what was happenning in Mordor...if you're familiar with the frog in a pot of water theory (turn up the temp very slowly and it will be boiled alive without ever noticing it was in danger) I believe it was a fairly similar situation with Sauron's rise to power. Combined with simple denial.

The Old Toby went to his head.

While we are most familiar with the great Rings, there were many essays into the craft before the Rings of Power were created. Gandalf assumed it was one of these lesser rings but knew that it shouldn't be taken lightly. It wasn't until he saw how it affected Bilbo (his unwillingness to part with it and how it prevented him from aging) that he got curious about the ring. He researched it for 17 years and even caught Gollum to learn the truth of what the Ring actually was.

He was high on the Halfling's leaf...

I believe Gandalf just assumed it was just "a" magic ring.

Sauron was seemingly active during the time Bilbo acquire the ring (in "The Hobbit"), as there is mention of Gandalf taking care of some business with a "Necromancer" who is in fact Sauron.

Now I have a question.

Could Gandalf see Bilbo (or anyone else) who was wearing the Ring? Could the Elves see someone wearing the Ring?

I ask this because the Ring did not so much make the wearer invisible as it pushed them into an "astral plane" or dark dimension. I believe that the Elves exist in both this astral plane as well as the regular reality. Notice in FOTR, as Frodo is slipping into the dark dimension, when he sees Arwen he sees her as an angelic being and not how she appears to the other Hobbits and Aragorn.

Would other creatures, such as the Elves, Balrogs, Nazgul, and Istari appear differently in each others eyes than would the eyes of men and hobbits?

Well in terms of the movie......when Frodo saw the wraiths before he was stabbed in FOTR, he saw them as ghostly beings right?

Probably because he'd never seen it or saw it used before - he didn't come on to the scene until about 1000 years after the ring was lost.

Also, Saruman was intentionally misleading Gandalf about the ring, as he wanted it for himself.

The ring inhibited the vision of the wearer. It didn't "push them" somewhere else.

What Jackson was intending to show was that when Frodo put the ring on, his vision was altered, and that wearing the ring alerted Sauron and the Nazgul.

The Nazgul are usually invisible beneath their robes, but because they are bound to the ring, the wearer can see their true forms.

I have another question:

According to THE MOVIE narration, "Something happened The Ring didn't expect", Bilbo got The Ring after it "left" Gollum.

I read "THE HOBBIT" but I can't remember...DID THE RING NOT SEE BILBO IN IT'S PATH? It would seem to me it did.

The ring has motive, but it is still a ring. It can't move of its own volition or anything like that.

It can "suggest" to Gollum not to remember to put it on, or to leave it somewhere, but only when Gollum is in a frame of mind to forget it.

I think the ring "thought" that it was time to be transported back to Mordor after 500 years, and "hoped" that an orc/goblin would find it where Gollum had "forgotten" it.

Also, hobbits are not as affected by the ring as others. (Gollum was also a hobbit type, but hey a few years can affect you...)

So, indeed, I'm sure the ring was "shouting" "i'm not here, pass me by, pass me by, look the other way", but Bilbo saw it anyway.

And the ring certainly didn't expect another hobbit in addition to Smeagol in the middle of the caves of the Misty Mountains.

Thanks Seeker. Interesting posts.

it is my understanding that it does. it removes you from the "normal" plane of reality, hence the "disappearing".

I've always had a problem with they way the movie portrays Elrond's attitude towards Isildur and the whole "men are weak" thing.

Sure, Isildur wouldn't throw the ring into the cracks of doom, but a) the ring is most powerful where it was forged, and b) he had just cut it from Sauron's hand. Surely there was more than a little residual of Sauron's presence left at that time.

It's no surprise that Isildur was enthralled with its power and expecting him to be able to wantonly destroy it at that point is a little one sided. With his attitude, maybe Elrond should host an elvish talk radio show.

I think Tolkien wrote somewhere that NO ONE could have willingly thrown the Ring into the fire.

GREAT POINT!!!