Intelligence

Intelligence is one of the six character abilities. It determines which levels of spells can be cast by mages, bards, specialist mages and sorcerers, the chance a spell can be written down in the spellbook from reading a scroll, it adds a bonus/penalty to lore points, which are needed to identify magical items and for mages and bards, it determines how many different spell of one level may be memorised in the personal spellbook. For sorcerers, the amount of spell for each level is determined by the level of the mage. For non-wizard class groups, excluding bards, intelligence only adds a bonus to lore bonus, so it's wiser to remove points from intelligence to the other character abilities when creating a character.

Permanent intelligence boosts

 * Tome of Clear Thought in Baldur's Gate (game) and Baldur's Gate: Enhanced Edition.
 * Machine of Lum the Mad in Baldur's Gate II: Throne of Bhaal.

Temporary intelligence altering items

 * Potion of Genius
 * Potion of Mind Focusing