The following features of views were discussed in this chapter:

• The concept of view is highly flexible and has significant potential for future SE.

• Views can exist within a model space dimension or cut across dimensions.

• In a composition hierarchy, views can focus on similarities of levels, or on differences between levels.

• Views can be nested.

• System behavior and system change can be regarded as disjoint activities, as in TSE; or as two views of a system, as in CS.

• Defined worlds are views.

• An SOI is a view and has several commonly associated views.

• Different areas of science consider different views of the same overall world.

• Views can help resolve the competing hierarchies problem.

• Architecture frameworks have put forward a variety of views. As SE matures, conventional sets of views will likely emerge.

• The concept of layered architecture can be illuminated by views and the idea of leverage.

• Views can help address the limits of modularity facing the aspect-oriented development community.

• Views are a natural way of dealing with dualities and contrasts that are a prominent characteristic of CS and to some extent TS.

• A preliminary set of categories or types of views is offered but a more mature set will emerge from a combination of research and practice.