Here's what you need to know about Palantiri:
* Purpose: Palantiri were created by the Númenóreans to communicate over long distances and to see events happening elsewhere. They were also used to peer into the past and future, though this power was often clouded by the wielder's own desires and perceptions.
* How They Work: They work by connecting to a network of other Palantiri, allowing someone to see through the eyes of someone holding another stone. The stones can also be used to project images and thoughts into the mind of the other user.
* In The Two Towers: In the book, Saruman is attempting to use the Palantir of Orthanc to spy on the other Palantiri and control the minds of their users. Aragorn, in Rivendell, is trying to resist the influence of Saruman through the Palantir of Orthanc.
* In the Movie: The movie adaptation simplifies the way the Palantiri work, focusing on their use as a "seeing" device, rather than the communication aspect.
The Palantiri play a major role in the events of The Two Towers, and they continue to be important throughout the rest of the Lord of the Rings trilogy. They are powerful artifacts with the potential for both good and evil, and their use is a constant source of danger and intrigue.