Government and Binding theory (GB) is the version of the Principles and Parameters approach. GB is a modular theory which divides grammar into a number of distinct subcomponents with a powerful transformational component. The basic idea is that children are biologically endowed with a set of principles, which are invariant across languages, and a set of parameters. The most recent outgrowth of the approach is the Minimalist Program (MP). MP explores the possibility that the content attributed to universal grammar (UG) is an optimal way of satisfying requirements imposed on the language faculty by the external systems. Government and Binding Theory and the Minimalist Program are two implementations of the Principles and Parameters approach, with the Minimalist Program building upon Government and Binding Theory. Minimalism attempts not only to explain the properties of the language faculty but also to answer the question why these properties are the way they are.