In this Chapter, we will give an overview of the trend in international efforts in criminal justice, escape of offenders to foreign countries and their extradition, and international assistance in criminal investigation and justice.
  In the recent circumstances of crime in Japan, we can see internationalization of crimes such as increasing offenses committed abroad as well as internationalization of offenders such as increasing offenses committed by visiting foreign nationals. Consequently, there are a great number of offenses that require international cooperation in criminal investigation and justice such as collecting evidence that exists abroad, arresting offenders who have escaped abroad and extraditing them to their home countries, and cooperation with foreign countries has developed accordingly.
  International cooperation is indispensable for properly dealing with transnational drug tracking, terrorism, and organized crimes committed by transnational organized crime groups, and various measures are being taken to strengthen international cooperation at the United Nations and summit meetings of leading countries. Recently, in addition to international cooperation in law enforcement, positive measures are also being taken to achieve international cooperation in order to develop international standards for harmonizing criminal justice systems of various countries (not limited to legal norms such as conventions).
  Along with the economic and social globalization, international transfer of human resources, goods, money and information has been facilitated due to the progress in information and communication technology and transportation, which has caused a globalization of crimes. For instance, it has become easier to transfer offenders, firearms and drugs across national borders and to collude with accomplices abroad. Furthermore, it has become possible to transfer crime proceeds instantly across national borders for the purpose of money laundering. Cybercrimes are also being committed in the borderless realm of the Internet known as cyberspace. In order to take effective measures to deal with these modern crimes that are becoming more global in scale, it is insufficient for individual countries merely to take measures to prevent crimes in their own territories; rather, it is necessary to reduce the number of countries and regions in the world with lax regulations so as not to allow the existence of havens for offenders. Based on such recognition, international cooperation has been promoted since the 1990s with the aim of harmonizing criminal justice systems at various international forums such as the United Nations and summit meetings of leading countries.