International law defines the legal responsibilities of States in their conduct with each other and in their treatment of individuals within State boundaries. It encompasses a wide range of subjects, such as human rights, disarmament, international crime and refugee issues. It also regulates the global commons, including oceans and outer space, world trade and global communications.

The Charter of the United Nations sets as one of its primary objectives the development and maintenance of international law. To this end, the United Nations General Assembly and the International Court of Justice are the principal deliberative bodies on matters relating to international law.

Among the sources of international law are treaties, conventions, custom and case law. International organizations, such as the United Nations and Interpol, also create binding law through resolutions that address situations threatening international peace and security. International courts and tribunals also issue binding opinions that are enforceable against the states parties to the proceeding.

Lawyers today, regardless of the nature of their practice, encounter an increasing number of international legal issues. The growth of the global economy, modern transportation and communication systems that cross borders and the international presence of corporations increase the likelihood that a matter will have an international dimension. Additionally, the proliferation of international terrorism and other forms of violent and non-violent international criminal activity require greater international cooperation. All of these factors increase the likelihood that a lawyer will encounter, or be asked to advise clients on, international legal issues.