The ultimate goal of the FuturICT Flagship is to understand and manage complex, global, socially interactive systems, with a focus on sustainability and resilience. Revealing the hidden laws and processes underlying societies constitutes the most pressing scientific grand challenge of our century and is equally important for the development of novel robust, trustworthy and adaptive information and communication technologies (ICT), based on socially inspired paradigms.Integrating ICT, Complexity Science and the Social Sciences will unleash a paradigm shift, facilitating a symbiotic co-evolution of ICT and society. Data from our complex globe-spanning ICT system will be leveraged to develop models of techno-socio-economic systems. In turn, insight from these models will inform the development of a new generation of socially adaptive, self-organised ICT systems.FuturICT as a whole will act as a Knowledge Accelerator, turning massive data into knowledge and technological progress. In this way, FuturICT will create the scientific methods and ICT platforms needed to address planetary-scale challenges and opportunities in the 21st century. Specifically, FuturICT will build a sophisticated simulation, visualization and participation platform, known as the Living Earth Platform. This platform will power Crisis Observatories, to detect and mitigate crises, and Participatory Platforms, to support decision-making for policy-makers and citizens.In this Coordination Action, we propose activities to develop our scientific vision and roadmap, secure stakeholder commitment, establish the FuturICT legal and operational infrastructure, and build on our remarkable success in uniting previously fragmented research communities. Through these activities, the Coordination Action will allow Europe to grasp this unique opportunity for groundbreaking progress in science and ICT, with great impacts for society, governance and industry by launching the FuturICT Flagship in 2013.