The index transforms the reading experience from passive to immersive:
| Location | Region | Importance | | :--- | :--- | :--- | | | The Spine (mountains) | Eragon’s home village. A backward frontier town that rises to rebel against the Empire. | | The Spine | Mountain range | A dangerous, superstitious mountain range that protects Carvahall from the Empire. | | Teirm | Coastal city | A port city; home to Jeod (Brom’s ally). Where Eragon first learns about the Varden. | | Dras-Leona | Southern Empire | A corrupt, religious city under the influence of the Helgrind cult. Site of a major battle. | | Gil’ead | Empire | A fortified city where Arya was imprisoned. | | Farthen Dûr | The Beor Mountains | The underground capital of the Dwarves and the Varden. Built inside a volcano. | | Tronjheim | Inside Farthen Dûr | A massive, multi-level city carved from black marble. | | Ellesméra | Du Weldenvarden (forest) | The elven capital. A magical city in giant trees. | | Ceris | Du Weldenvarden | The "city of light" – a beautiful but smaller elven settlement. | | The Hadarac Desert | Central Alagaësia | A deadly wasteland separating the Empire from the Beors. | | Helgrind | Near Dras-Leona | A three-pronged mountain where the Ra’zac and Lethrblaka nest. | | Urû’baen (Ilirea) | Empire | The capital of the Empire, later renamed after the war. Home of Galbatorix’s citadel. | | Vroengard Island | Northeast ocean | The original home of the Dragon Riders. Now a radioactive, cursed wasteland due to a Rider’s suicide spell. | index of eragon
In the Ancient Language, one cannot lie. The glossary allows readers to "verify" the intent of characters' spells. The index transforms the reading experience from passive