Graph Rewrite And Transformation (GReAT) is a graph-transformation based language that supports the high-level specification of complex model transformation programs. In this language, one describes the transformations as sequenced graph rewriting rules that operate on the input models and construct an output model. The rules specify complex rewriting operations in a concise, yet precise manner, in the form of a matching pattern and a subgraph to be created as the result of the application of the rule. The rules (1) always operate in a context: a specific subgraph of the input, and (2) are explicitly sequenced for efficient execution. The rules are specified visually using a graphical model builder tool.