The Commission on European Family Law published its “Principles of European Family Law Regarding Parental Responsibilities” in 2007 as a contribution towards the establishment of a European Family Law. Only by empirical testing of the Principles in a number of legal systems can one demonstrate whether they are acceptable and/or are regarded as an improvement on existing national laws. This edited volume seeks to test the Principles in a range of legal systems, some untested: Malta, Estonia, Romania, Scotland and Turkey; some already considered by the CEFL: Denmark and England; and in so doing to assess these legal systems in view of the Principles, and the Principles in view of these legal systems. The final part of the volume is a comparative assessment of the findings, considering the Principles as harmonious ideals, and analysing the shortfalls in these ideals.