Science in the 21st century is more than ever a global venture. International scientific collaboration is on the rise especially when and where it enables increased research eficiency and efectiveness and when it permits scientific challenges of a large scale and scope to be addressed. Thus the scientific hubs of a multipolar scientific world are becoming more and more interconnected. Scientists are driven by opportunities to raise the quality, speed and impact of their research. They seek to work with the best people and in or with the best institutions globally, while ofen maintaining strong links with their places of origin over space and time. As they become more mobile and as their informal connections grow, diferent types of scientific communities and networks are created, influencing the way scientists interact and pursue their research and innovation agendas. Such research communities - real or virtual - facilitate the extension from the local or national level to the global level in the way science is conducted. In the process, they mediate international collaboration and broaden research horizons. Yet little is understood about these networks and their dynamics. From a European perspective, it is interesting to recognize such national communities of European scientists in the US and to understand the valuable role they play for their members as well as their potential to strengthen transatlantic S&T cooperation. From the perspective of the communities themselves, it would seem to be beneficial for them to learn more about each other, their ways of working and of the potential for enhancing their utility and impact. This 1st Annual Meeting aims to explore such questions with a view to identifying more precisely how to enhance the benefits that can be derived from networking with existing and future networks of scientific diasporas in the US, as well as the type of concrete actions which could be taken to bring this about.