The Hall of Ancient Thought was an old structure that was on the planet Vulcan which resided at Mount Seleya. It was a vast, dark maze of passageways which were filled with thousands of Vre'katra that contained the essence of certain Vulcans. The entrance into the Hall contained a massive doorway made of stone which protected a chamber that consisted of a high vast cavern that was linked with glowing vrekatras which were full of the knowledge of centuries. This room was sufficiently lit by luminous force fields that surrounded the receptables that held the katras. These containers held the name of the individual interned which was carved in old Vulcan script. (TOS novel: Star Trek V: The Final Frontier)
Sometime before Surak's message of logic took hold of the Vulcan race, the tyrannical Mind Lord known as Zakal the Terrible had his katra removed and placed within the Hall. (TOS novel: The Lost Years) Thousands of years ago, during ancient Vulcan history, Surak travelled to the Hall of Ancient Thought in order to speak to the Adepts of Seleya and the Adepts of Gol about their participation in a possible exodus from the Mother World. During the journey to Mount Seleya, Surak lost one of his students, Varen, to te-Vikram raiders and thus deposited his katra within the Hall. (TOS novel: Exodus)
At some point in the 23rd century, Sybok attacked the Watcher Storel and stole from his mind the exact layout of the Hall of Ancient Thought in order to recover the vre'katra of his mother T'Rea. (TOS novel: Star Trek V: The Final Frontier)
- Last Unicorn RPG module: The Way of Kolinahr: The Vulcans states that the Hall is located within the Kolinahru Monastery though other sources say it is located within Mount Seleya.