How do lawgivers define what makes a good parent? NADJMA YASSARI is interested in the impact of the principle of the best interests of the child on custody decisions in the Middle East and countries with common heritage from Islamic family law. As she explains in this video, her research team adopted a comparative inner-Islamic approach. They did not only examine the legal aspects of the question but they also put each country’s laws and rules in a social, historical and cultural context. They discovered that while there was a historical continuity on the use and the application of the principle of best interests in custody rules in pre-modern Islamic law, the legislatures of modern Muslim Nation states introduced and applied that principle to varying degrees in statutory laws and court practice. Their findings enhance the understanding of Islamic concepts of family and custody and might, for instance, help the integration processes of immigrants from Muslim countries to Europe.