The book is based on the author’s dissertation, written under the supervision of Prof. Hélène Ruiz Fabri at the University of Luxembourg. This book offers a detailed analysis of judicial activism in international adjudication using the WTO Appellate Body and the European Court of Justice as the comparative subjects. It discuss the negative and positive aspects of judicial activism by incorporating sociological elements in its doctrinal approach. The objective of the book is to provide a scientific understanding of judicial activism in international adjudication and explore the means of international courts and tribunals to engage in judicial activism, taking into account other elements operating inside and outside the courtrooms.