The study is a comparative examination of key issues such as definitions of serious crime, central defence rights and detention conditions in the 30 member state jurisdictions of the EU. It also addresses the rights of defendants and victims to participate actively in criminal procedures. The core conclusion reached is that criminal justice is achieved in such diverse ways in the member states that an autonomous EU position must be reached if an EU criminal justice area is to be developed. Firstly the legitimate reach of any EU criminal justice system must be determined. The study then highlights that an EU order oriented towards the highest standards of protection and participation will ensure the least disappointment and disillusion of citizens affected by EU criminal justice mechanisms. Fundamentally a conception of EU criminal justice as serving EU citizens and thus constitutional rights holders - be they victim, witness or defendant - is highlighted as necessary.