Private international law is a sector of international law that oversees all legal entanglements that involve foreign law elements. Private international law is also referred to as conflict of laws, as international law usually trumps federal or national laws if there is conflict and the countries in question have signed an agreement to submit to an international ruling.

Private international law determines, if there is a conflict of laws, who has jurisdiction over the specific case and which laws are to be applied by the country that is given jurisdictional rights.

This type of law has been practiced by ages, and was first implemented by the Romans, who established a tribunal to reside over cases brought by foreign states that had a conflict of laws with regards to a criminal, etc. the Roman courts might decide to apply the law of one nation over both Roman law and the other nation.

Thus, private international law is largely used to settle disputes between foreign countries; however, awarding a case to one may mean a backlash from the other. Because of this, international rulings often take into consideration the reality of the situation with regards to international law, and may come to a decision that both countries legal factors are okay with.

In contrast to private international law, public international law is not concerned with conflict of laws; it is concerned with the configuration and conduct of states, international organizations and sometimes commercial industry, like a multinational corporation.

Also called the 'law of nations,' international law deals with the possession of territory, the immunity of the state and its legal responsibility in regards to its conduct with other states. It also deals with the behavior towards citizens and non-citizens within the confines of the state. This includes rights of aliens, groups, refugees, human rights violations, crimes committed internationally, applications and problems concerning nationality, and much more.

International law attempts to maintain good relations and international peace, avoid any armed conflicts where possible, maintain arms control, concerns itself with environmental issues, communications and space technology; in essence, it simply deals with every aspect of law on an international scale, from wars to the environment and everything in between.