Perhaps the greatest strength of an object-oriented approach to development is that it offers a mechanism that captures a model of the real world. - Grady Booch

In object-oriented analysis, we seek to model the world by identifying the classes and objects that form the vocabulary of the problem domain, and in object-oriented design, we invent the abstractions and mechanisms that provide the behavior that this model requires.

Object-oriented design is a method of design encompassing the process of object-oriented decomposition and a notation for depicting both logical and physical as well as static and dynamic models of the system under design.

The object-oriented paradigm is useful when building software systems where there is a hierarchy defined as a ranking or ordering of abstractions.