I.5.5. Working in Layers

When you sit in a theater to watch a show production, the experience is very three-dimensional. As you sit facing the stage, your depth perception tells you that the objects placed closer to you appear larger, and objects that appear far away are generally smaller. Behind all these objects is the background. Sometimes it's a set, and sometimes it's just a curtain. Now while you sit in front of your computer, Office documents offer the same sort of 3D experience.

I.5.5.1. Starting at the back

Everything you see in Office is on a layer. Some things are closer to you than others. The layer that's furthest to the back is the background layer.