From ErfWiki

Contents 1 Proposed Canon 2 Speculation 2.1 Uses 2.2 Features

Proposed Canon

Eyebooks are magic items created by the Eyemancer caster link-up in Gobwin Knob.
Being a magic item they continue to function even after the Eyemancer link-up was broken.

Speculation

Uses

• Communication between Eyebook holders
• Store information like a Journal or Klog

Features

• Can be resized to match the size of the user
• Can be modded by the user
  • Different username
  • Different alert sounds. (These might be references to Monkey Combat)
• Does not need to be written in; the user need only subvocalize to use it.