Alexander Nahum Sack
Alexander Nahum Sack or Aleksandr Naumovich Zak, (5 October 1890 in Moscow, Russia – 1955 in New York City, United States), was a jurisprudence expert and professor of Russian law, specialized in international financial legislation. After teaching in Saint Petersburg university, he left the Soviet Russia in 1921 to settle in Estonia, where he advised the government in monetary issues. He also gained the Estonian citizenship, but moved to Paris in 1925. He taught at the Institute of Political Studies in Paris and in the International Law Academy in The Hague before moving to London in 1929 to  work as an expert for Equitable Life Insurance. Work for this company led him to New York, where he definitely established in 1930. After obtaining the USA nationality, he was invited to teach at Northwestern University and New York University until 1943, working as a free-lance law expert for the Justice Department until 1947. Sack is best known for his formalization of the odious debt doctrine in his work "Les effets des transformations des Etats sur leurs dettes publiques et autres obligations financières" ("Effects of the transformations of the states in their public debts and other financial obligations"), published  in Paris in 1927, when he taught law at the Institute of Political Studies. Alexander Sack synthetised the concept of odious debt based on precedents from the 19th century, such as the Mexican government rejection to pay debts acquired by the emperor Maximilian I, and the rejection by the USA, once annexed Cuba, to pay the debts acquired when it was a Spanish colony.