The Eye Between the Worlds was Manannan's computer that had been brought over from the Other World during a withdrawal or by other means.
Background[]
The Eye Between Worlds belonged to Manannan and he kept it in his study on a bookshelf. By use of magic it allowed its user to communicate to computers in the Other World. When Derek Karlavaegen took over the house after Manannan was turned into a cat, he began to record history on the Eye and sent the documents to the Other World to Peter Spear and others to read.
Derek Karlavaegen described it as a machine that looks much like a metal head (a talking head), but with only one very large glass eye and an open jaw containing near one hundred teeth. Each of these teeth has a letter, number, or symbol inscribed upon it, that allows him to communicate with the Other World. When a certain tooth is pressed, light appears on the eye's glass surface.
It talks, not with sounds, but with words that crawl across it and with pictures that draw themselves before the users eyes. By pressing the teeth, one can make their thoughts and words appear on the eye's surface. Unlike most machines, it has no parts which move.[1]
Priscilla magically gave The Wanderer one of these computers to help on his journey as well.
A machine, technological equivalent to the modern computer, (perhaps eleventh century origin) possibly created by Manannan, or some other very great sorcerer (some speculate Pope Sylvester). Alternatively, may have been made by Manannan based on Sylvester's designs. Whatever the case, it made its way into Manannan's hands.
"Any technology, sufficiently advanced, is indistinguishable from magic."-Arthur C. Clarke. If technology can emulate magic, perhaps magic can emulate technology?[2]
Derek Karlavaegen speculates the reason why the Wizard contrived it, was to talk to the Other World, or perhaps to recruit allies whom he could help withdraw to Daventry so that he and his evil family might rule cruelly over the entire universe. Or perhaps Manannan was just curious about the Other World.[3]
Behind the scenes[]
King's Quest I and II references cards have this line; "Your computer will be your hands, eyes and ears."
Get a copy of King's Quest 3: To Heir is Human. Look at the bookshelves in Manannan's study. Notice what appears to be a computer screen sitting on one of the shelves.[4]
The Eye Between the Worlds is inspired by the computer in Wizard and the Princess & Adventures in Serenia and later re-releases of Wizards and the Princess given to 'happy wanderer/the wanderer' to help the player on adventure, as well as the legends of Pope Sylvester II's robotic 'brazen brain'.
The manual for Wizard and the Wizard and the Princess describes the 'computer' as a kind of puppet which allows the player to control things, explore, or pick up things, and protects the hero from being hurt directly by the spells of the evil wizard.
Another computer can be seen flying by the space station window in the Beam Me easter egg in KQ4AGI.