This thesis will examine how legal systems deal with the phenomenon of multiple assumptions of jurisdiction over the same dispute. We will first look at public international law rules on jurisdiction, regulating (or not regulating) conflicting states' interests, which will give only modest guidance. In view of those rules, the subsequent chapters will deal with various national laws relating to the possibility of parallel proceedings in the courts of more than one country, and thus the possibility of the emergence of conflicting orders or judgments.