Book excerpt: The second instance of the international summer school on Generative and Transformational Techniques in Software Engineering (GTTSE 2007) was held in Braga, Portugal, during July 2–7, 2007. This volume contains an augmented selection of the material presented at the school, including full tutorials, short tutorials, and contributions to the participants workshop. The GTTSE summer school series brings together PhD students, lecturers, technology presenters, as well as other researchers and practitioners who are interested in the generation and the transformation of programs, data, models, metamodels, documentation, and entire software systems. This concerns many areas of software engineering: software reverse and re-engineering, model-driven engineering, automated software engineering, generic language technology, to name a few. These areas di?er with regard to the speci?c sorts of metamodels (or grammars, schemas, formats etc.) that underlie the involved artifacts, and with regard to the speci?c techniques that are employed for the generation and the transformation of the artifacts. The ?rst instance of the school was held in 2005 and its proceedings appeared as volume 4143 in the LNCS series.