Holocrons

The Holocrons 

A holocron, short for holographic chronicle, was an organic crystal-lattice device, in which the Jedi of old stored phenomenal quantities of data, as well as the holocron's gatekeeper. The Sith also had their own form of holocron technology, and they seem to predate the Jedi in using the technology by at least three thousand years.

"Meant to be a teaching device. Jedi record their experiences into them. They're interactive so you can talk with them."

―Quinlan Vos