This research project is about innovation in the public sector. In a time of economic crisis and continued cost-cutting, public sector innovation is essential for governments in order to maintain service standards and find radical solutions for complex challenges. The research question of the project asks what are the main characteristics and driving forces of the public service innovation system and do they differ across countries? The research has four perspectives through which the public sector innovation process is analysed: managerial, learning, technological, and systems perspective. As data on public sector innovation is quite rare, this research provides a unique combination of theoretical foundations and exploratory cross-country survey on public sector technological innovations in four European countries – the UK, Denmark, Finland and Estonia.