[Guinevere]

This chapter is full of suspense - the description of the tunnel is incredibly creepy and full of foreboding. The utter darkness and the stench are something which of course couldn't be conveyed to the film and I think the scene is much more effectful in the book. It reminds me somehow of a "ghost-train" or "tunnel of horror" at a fun fair, especially the unseen things brushing their heads and hands in the dark.
I note that in the tunnel, Frodo is the one who is more resolute and couragious.

Littlemanpoet wrote
Anyway, one thing that really stood out to me was how Sam praised Frodo for his heroic act of chasing Shelob away, saying that it would go down in song. Little did he know that his own actions in the following moments would completely overshadow those of Master Frodo

Several movie-oriented LotR-fans I know don't even remember Frodo's bravery! But I just love this scene: (probably now even more, because it is such a contrast to the helpless movie-Frodo...)

Then Frodo's heart flamed within him , and without thinking what he did, wheter it was folly or dispair or courage, he took the Phial in his left hand, and with his right hand drew his sword. Sting flashed out and the sharp elven-blade sparkled in the silver light, but at its edges a blue fire flicked. Then holding the star aloft and the bright sword advanced, Frodo, hobbit of the Shire walked steadily down to meet the eyes.

It strikes me that the Phial by itself didn't scare Shelob, nor even Frodo's call "Aiya Earendil Elenion ancalima!" It is only when Frodo gathers his own courage that it works!
Btw It took me a heck of a time to find out what "ancalima" means! Now I know more, and Davem's post about this is fascinating!
Apparently Sting shines blue also in Shelob's presence - not only that of orcs!

Hilde wrote:
Frodo and Sam discover the true shape of Shelob only very late in the chapter.

In fact, Frodo never sees her at all, since she comes at him from behind. Later, in Cirith Ungol, he asks Sam: "Something hit me, didn't it?"