This book maps and briefly analyses political action in the field of cybersecurity in Portugal, from the moment that network and information system security issues appeared on the political agenda until 2014, with the implementation of the National Cybersecurity Centre. The public policy cycle is used as a model for analysing and mapping the actors and political measures adopted in Portugal in this area. The relevance of this research is linked, on the one hand, to the fact that, despite already existing in other countries and European and international guidelines pointing in this direction, there is still no integrated public cybersecurity policy in Portugal (at the time of writing) and, on the other hand, considering that this area should be a strategic factor in the public policies of developed countries (those whose normal functioning of the services that maintain society as we know it depends on infrastructure supported by networks and information systems). The aim is therefore to draw attention to the importance of this issue and to contribute in some way to the development of knowledge in this area.