This book addresses the international legal questions arising from the 'right of visit on the high seas' in the 21st century. This right is considered the most significant exception to the fundamental principle of the freedom of the high seas (the freedom, in peacetime, to remain free of interference by ships of another flag). It is this freedom that has been challenged by a recent significant increase in interceptions to counter the threats of international terrorism and the proliferation of weapons of mass destruction, or to suppress transnational organized crime at sea, particularly the trafficking of narcotics and smuggling of migrants. The book questions whether the principle of non-interference has been so significantly curtailed as to have lost its relevance in the contemporary legal order of the oceans. The book begins with an historical and theoretical examination of the framework underlying interception. This historical survey informs the remainder of the work, which then looks at the legal framework of: the right of visit * contemporary challenges to the traditional right * interference on the high seas for the maintenance of international peace and security * interferences to maintain the 'bon usage' of the oceans (navigation and fishing) * piracy jure gentium and current counter-piracy operations off the coast of Somalia * problems posed by illegal, unregulated, and unreported fishing * interdiction operations to counter drug and people trafficking * recent interception operations in the Mediterranean Sea organized by FRONTEX. It is an interesting and useful book for all those concerned with the contemporary challenges to the legal order of the oceans. (Series: Studies in International Law - Vol. 43)