Chris van Allsburg created the above image for the cover of The Horse and His Boy by C. S. Lewis. It is a window into the land of Calormen, south of magical Narnia; the view invites you to imagine yourself traversing the bridge to the city of Tashbaan, where other wonderful vistas no doubt await.
Now consider the following work of art:
This map accompanies The Book of Ti'Ana by Rand Miller and David Wingrove (among others). It depicts the cavern of D'ni, located miles underground, and a tunnel that leads to the Earth's surface. Notice first that it is two maps: The bird's-eye view of the route spans most of the canvas, from the lake on the left to the volcano on the right. Below it is an elevation view of the same route which runs in parallel to the bird's-eye view. The relationship between the maps is emphasized by the layout: They both curve up and to the right, complementing each other.
The rest of the canvas is taken up by illustrations of small details relevant to the journey. As you trace the path from D'ni to the surface, your attention is drawn to these drawings, and your eye instinctively attempts to read the accompanying captions written in D'ni. But then your attention is drawn to a nearby compass rose line, which you follow back to the map's origin.
This is a piece of fantasy art, but it is also a functional document. It has an interactive quality to it: You can choose to explore the work by tracing a route on the map, or studying the drawings, or scrutinizing the cartographic legends and headings. And all the while, you remain very aware of the fact that you are reading a document.
If you become engrossed in this piece of art, you will not lose the sense of examining a document. And yet a part of you will become convinced that the world depicted really exists, far away underground.
Compare this fantasy with the picture of Tashbaan at the beginning of this article. Becoming engrossed in that artwork makes you forget that you are looking at a picture. You begin to feel that you are really in that other world.
The picture of Tashbaan invites you to enter a fantasy, leaving this world behind. The map of D'ni, on the other hand, allows you to explore a fantasy within the context of this world. These two modes of fantasy are satisfying in different ways.
