Tome of Clear Thought
Wondrous Item,
Very Rare
(cost 20000 gp)
Crafting Components
Parchment soaked in khalkos blood
This magical book dictates methodologies for more rational and logical thinking. Spending 48 hours over 6 days (or fewer) reading and following the book’s methodologies increases your Intelligence score and your maximum Intelligence score by 2. The tome then becomes a mundane item for a century before it regains its magic.
Source