An adaptation can become the most iconic version of a story, with the number of people who have read J.R.R. Tolkien's Lord of the Rings books being significantly higher than those who have seen Peter Jackson's movies.
This unique reality leads to some elements of the books appearing differently in the cultural imagination, such as the iconic symbol of Sauron, which is more complex in the source material.
Lord of the Rings' survival in the ages was largely due to its unique and dynamic prose, which is often non-specific. This has caused frustration among fans who spend time trying to understand specific details without much evidence. Peter Jackson struggled to depict the books in a visual medium, resulting in several clashes that leave many details unclear.
What is the Eye of Sauron?
In the movies, the Eye of Sauron, a flaming eye that watches over Mordor, is a worldly manifestation of his soul that lost all physical form in the War of the Ring. It casts a red spotlight over the land, like a floodlight searching for escaped prisoners. The Eye sits in the Window of the Eye, the curved spire at the top of Barad-dûr.
The Eye appears in Frodo's mind several times, tormenting him from hundreds of miles away. In The Return of the King, a scene zooms into the Eye, revealing the Dark Lord's humanoid form in the middle, contradicting the logical suggestion that the Eye is Sauron's physical form. This leaves the question of its physical makeup open to interpretation.
In the books, the Eye of Sauron is a symbol referring to Sauron's will, network of spies, and omnipotent vision. His Orcs have shields with a large red eye, demonstrating his power. The books rarely depict a flaming eye, but it does appear a couple of times. The films use the flaming eyeball interpretation, while the books depict him as a phantom. The flaming eyeball is seen in two scenes: Frodo and Sam see it in the Window of the Eye, a glass window on the tower of Barad-dûr, and Frodo sees it in Galadriel's mirror, revealing the mental warfare Sauron waged against his enemies.
The book describes it like this, "In the abyss there appeared a single Eye that slowly grew, until it filled nearly all the Mirror. So terrible was it that Frodo stood rooted, unable to cry out or to withdraw his gaze. The Eye was rimmed with fire, but was itself glazed, yellow as a cat's, watchful and intent, and the black slit of its pupil opened on a pit, a window into nothing."
Eye of Sauron: How was it formed and what is its purpose
The Eye of Sauron is a character who loses his physical form and becomes a wayward spirit. In the first film, his body dies when Isildur hacks off his finger. In the books, he drowns when the god Eru IIlúvatar defeats him and sends Númenor into the sea, killing Sauron and his companions. Sauron's drowning robs him of his body, allowing him to take on new forms to disguise himself. He spends time recovering from Eru's attack before returning in the questionable form of the book. He remains in Barad-dûr but gains the ability to cast shadows over Middle-earth during the Third Age.
The Eye of Sauron is a mental weapon that constantly invades enemies' minds, causing fear and horror. Gandalf battles the Eye of Mordor, but he remains capable. Frodo and Galadriel feel the Eye peering into them, and it strikes fear into their hearts. Even those who don't look at it can feel its intense hostility. The Eye represents Sauron's omniscience and power, creating an oppressive atmosphere of darkness by making armies more threatening and digging into enemy minds.
The Eye of Sauron is a great image. Even in the films, it does exactly what Sauron wants it to do. After he lost his physical form, he decided to dispense with the effort it took to deceive others. Now, he wants to make his intentions and abilities crystal clear. The Eye of Sauron is meant to see and be seen. The unease it creates in every onlooker is the point.