Layering is a way of organizing information into related groups in order to manage its complexity and to reinforce relationships within the information and selectively presenting those groups. Layering can either be two or three dimensional. In two dimnesional layering only one layer of infomation can be viewed at any one time and can be viewed in a linear or non-linear fashion. Linear layers are good for information that has a begining or an end, eg. a story. Non-linear layering are used to reinforce the relationships between the layers, eg. hierarchy, parallel and web. Three dimensional layering is a way of presenting several layers with the same space. eg. a modul window.