The cooperation in criminal matters between EU Member States has improved consistently over the last two decades. Main reason is the implementation of a series of dedicated instruments based on the principle of mutual recognition of decisions of judicial authorities that cover the prominent areas of judicial cooperation, except one: there is no specific EU instrument for the transfer of criminal proceedings. This is strange for two reasons. Firstly, the transfer of criminal proceedings is in fact used in daily practice. But, the transfer of criminal proceedings could, if used more effectively, help prevent impunity in a lot (more) of criminal cases with cross border aspects and present a less complicated alternative to, for example, issuing an EAW. Secondly, the current legal instruments that are used for the transfer of criminal proceedings offer little hold. In February 2019, the Romanian presidency of the EU tabled the idea of a new legislative proposal on the transfer of criminal proceedings. In the discussion on a follow up document in the Council the need to conduct a thorough analysis of the existing practice of the transfer of criminal proceedings has been stressed. There seems to be sufficient ground for such a research indeed, from a policy (gaps in the framework for effective judicial cooperation, basis for improvement, decision on the added value), scientific (interesting views on a key area of judicial cooperation) and practical angle (exchanging experiences, best practices). A good working legal system can prevent impunity in criminal cases with cross border aspects and can be of use in cases where the issue or execution of an EAW is not possible. This research project tries to answer these questions by offering a well-researched base for new best practices or possible future EU legislation and it provides discussions and mutual understanding between scholars, practitioners, policy makers and legislators from 9 MS on the afore mentioned subject.