Two issues are mainly discussed in this book, which currently seem to be under conflict at the EU level: the first one has to do with the fundamental human right of the protection of privacy and more specifically with the aspect of the protection of personal data, while the other is related to the combating against terrorism, namely the issue of security. A complicated situation was emerged, dealing with the different competences that the EU obtains on each field. The question arised is whether the EU can handle effectively the matter, despite the absence of a uniform legal regime at present.Eventually, as it was observed, the European Union managed, through a difficult and time consuming procedure to find its way to handle the issue, despite the existence of the endogenous structural complexities, thus achieving to formulate a new path under which this greatly debated matter will be dealt with thereof.