The Great Holocron was an ancient, twelve-sided holocron as defined in Legends continuity.
Located within the Jedi Archives situated on Coruscant, the Great Holocron served as the central piece of the Jedi Temple's library collection. It held a significant quantity of data, accessible only to a Jedi Master prepared to unlock it, while Jedi initiates were encouraged to delve into its contents. Despite its accessibility, fully grasping its numerous secrets was considered unattainable—even Master Yoda, according to Archives Director Jocasta Nu, supposedly struggled with its profoundness.
Although the Great Holocron was engineered to reveal only information suitable for the user's level of understanding, inexperienced Padawans were permitted access under the careful supervision of the Archives Director, who was ready to intervene if a young Jedi ventured too deep.
After the Galactic Empire rose to power, the Great Holocron disappeared, most likely seized by troopers of the 501st Legion during the assault on the Jedi Temple that occurred during Order 66.
It was eventually found again by the New Jedi Order in 40 ABY and was then placed within the library of the Ossus Academy, where Master Tionne Solusar took care of it. She was uncertain about the authenticity of the artifact, unsure if it was the genuine Great Holocron or a skillfully created imitation. She would update the Holocron with data from recent eras to continue the work of former archivists before her.
Subjects covered included both basic and advanced techniques for lightsaber construction, the history of the Galactic Republic, philosophy, Sith history, lightsaber combat, and Jedi skills. The Great Holocron also featured discussions regarding the dark side of the Force and methods for resisting its allure.
Throughout the Order's existence, many Jedi contributed various pieces of information. Listed below are some of the submitted stories and journals:
- Arca Jeth on the Freedon Nadd Uprising [2]
- Brief references to the Ruusan campaign .
- Obi-Wan Kenobi's account of his encounters with the Sith Lords, Darth Maul and Darth Tyranus .
- Sar Agorn 's perspective on manipulating the Force .
- Saesee Tiin's address to a group of younglings concerning telepathy. Also Tiin's report on the Scimitar .
- Dooku on the subject of lightsaber combat, overcoming arrogance, his departure from the Order, and a formal objection to the Council following the Battle of Baltizaar .
- Yoda discussing farsight and the Chosen One .
- Tholme describing the hazards associated with psychometry , using the example of Padawan Quinlan Vos .
- Oppo Rancisis focusing on Malacia .
- Yaddle discussing Morichro .
- Plo Koon addressing Electric Judgment and the Mission to Metellos .
- Kit Fisto providing information on waterproofing lightsabers .
- Ki-Adi-Mundi's report detailing the death of Sharad Hett .
- Cin Drallig describing the seven forms of lightsaber combat.
- Mace Windu discussing Vaapad and the origins of the Korunnai ; however, the latter entry might have been propaganda produced by the Galactic Empire .
- Rekpa De reflecting on victory and defeat.
- Danzigorro Potts reporting the demise of Xendor .
- Vima Sunrider explaining Ulic Qel-Droma's redemption.
- Tolaris Shim outlining the four stages of the dark side.
- Deesra Luur Jada recounting the era surrounding Revan's rule.
- Reidi Artom 's account of the Cularin system .
- Lanius Qel-Bertuk making reference to the Sith Temple located on Almas .
- Limited information about the Chu'unthor .
- Mentions of the prophecy regarding the Chosen One.
- Siri Tachi's insights into Anakin Skywalker .

Although it was not depicted in the movie, during the production of Attack of the Clones, the film's prop department created three holocrons for its Visual Dictionary: a Jedi holocron, a Sith holocron, and the Great Holocron.
- "The Great Holocron" on Wizards.com (content now obsolete; backup link)
- Star Wars: Attack of the Clones: The Visual Dictionary
- Star Wars: The Ultimate Visual Guide
- Star Wars: The Complete Visual Dictionary
- Jedi vs. Sith: The Essential Guide to the Force
- Star Wars Fandex Deluxe Edition
- The Complete Star Wars Encyclopedia
- Star Wars: The Ultimate Visual Guide: Updated and Expanded