Book excerpt: Judicial Cosmopolitanism: The Use of Foreign Law in Contemporary Constitutional Systems offers a detailed account of the use of foreign law by supreme and constitutional Courts of Europe, America and East Asia. The individual contributions highlight the ways in which the use of foreign law is carried out by the individual courts and the path that led the various Courts to recognize the relevance, for the purpose of the decision, to foreign law. The authors try to highlight reasons and types of the more and more frequent circulation of foreign precedents in the case law of most high courts. At the same time, they show the importance of this practice in the so-called neo constitutionalism.