Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A Platform-Independent Model (PIM) in software engineering is a model of a software system or business system, that is independent of the specific technological platform used to implement it. The term platform-independent model is most frequently used in the context of the model-driven architecture approach. This model-driven architecture approach corresponds the Object Management Group vision of Model Driven Engineering. The main idea is that it should be possible to use a Model Transformation Language to transform a Platform-independent model into a Platform-specific model. In order to achieve this transformation, one can use a language compliant to the newly defined QVT standard. Examples of such languages are VIATRA or ATLAS Transformation Language.