The scroll of knowledge is a reward from defeating the Gnome Champion of Champions, Glophren. After killing him, players may talk to Larxus and claim four scrolls of knowledge and 50,000.
The scrolls each give 10,000 experience in any combat skill (Attack, Strength, Constitution, Defence, Ranged, Magic, Prayer or Summoning) that is level 50 or above. Reading the scroll yields the following message: As you read the scroll, you learn some advanced combat techniques known only to champions. You gain 10000 <Skill> XP.
This is one of the few experience-granting items that can be banked.