The significance of this book, one of the essential works to examine the concept of "nationality" in international law, has been renewed by the emerging debate on the concept of citizenship in the context of the global human rights regime. Professor Donner starts from the basic rule that it is the right of each sovereign independent state to determine who are its nationals, as evidenced in their nationality legislation (the reserved domain) and in the practice of diplomatic protection. She proceeds with an analysis of any possible standards or rules set by public international law. This is a valuable study of one of the most fundamental issues in the law of nations.