How was James Tobin awarded the Noble Prize in Economics?

Name: James Tobin.
Real Name: James Tobin.
Country: United States.
Date of Birth: March 5, 1918.
Died: March 11, 2002.
Education: Master of Arts (AM degree) from Harvard University
Subjects Of Study: Financial market investment.
Popularly Known: Pioneering the Tobin Tax, a levy on foreign exchange transactions to reduce currency speculation.
Noble Prize Year: Nobel Prize for Peace in 1981, for his analysis of financial markets and their relations to expenditure decisions, employment, production and prices.