A crash course in changing the world.
I choose egyptian hieroglyphs, because it is very impressive how many thousands of years the knowledge has survived.
The hieroglyphic writing was used as a notation system for accounting, for doc**entation of significant events and for sacred texts. Only a certain circle of persons has the knowledge of the hieroglyphics. The Egyptians used as written media stone, clay and rolls of papyrus.
I think the hierglyphic writing is an important piece of information, because they contain a lot of historical knowledge.