Hans Kelsen was an international legal scholar who is best-known for his 'positivist' theory of law in which law is separated from ethical and moral issues.  Born to a Jewish family in Prague in 1881, Kelsen's parents relocated to Vienna when the young boy was just two years old.  

A capable student, Kelsen excelled in his studies and earned a law degree.  A few years later, he earned his teaching credential and published his first major work, Main Problems in the Theory of Public Law (1911).  At thirty-eight, he became a full professor at the University of Vienna. 

The following fifteen years were among the most productive in Kelsen's life.  In 1920, he was instrumental in the drafting of the Austrian Constitution, enacted shortly thereafter, was appointed to the country's Constitutional Court, and continued to publish.

As the Nazis rose to power, Kelsen became something of an itinerant scholar— holding posts in Germany and Switzerland before finally joining the faculty at Harvard in 1940.  Finally, in 1942 he took a position at University of California at Berkeley, which he held until his retirement in 1952.

Kelsen's main contributions to legal scholarship include development of the European Constitutional Court System in which separate Constitutional Courts preside over Constitutional matters, a general theory of legal positivism, and work in international law at institutions such as the United Nations.

Kelson died in 1973.