For the past 20 years the TOOLS conferences have continuously spread new technologies in the world of object-orientation, component technology and so- ware engineering in general. They constitute a particularly important forum for software researchers and practitioners to present work that relies on producing tools. This year’s TOOLS continued the tradition and presented a strong program thatincluded originalcontributionsin allmajor?elds ofthe object-orientedp- adigm. As in TOOLS 2008, the concept of model occupied a considerable place; but other topics such as re?ection,aspects, modelling languages,debugging,and virtual machines design were also strongly represented. While most conferences had a decrease in the number of submitted papers, TOOLS made the choice of quality and decided to lower its acceptance rate to 25%,asa ?xedmaximumannouncedin the Callfor Papers.Out of67submitted contributions, the reviewing process led to the selection of 17 as full papers. For the ?rst time, two short papers were also accepted for presentation at the conference.