sentences:  He went on to study Russian language and area studies at the Russian Institute at Columbia University, and became convinced that the principal challenge of American diplomacy in the post World War II period would be dealing with the Soviet Union.After his 1953 appointment to a position as Russian Instructor at Dartmouth College, he supplemented his income by preparing an index to Joseph Stalin's collected works on contract with the State Department.Because in 1956 the Soviet Union was a closed society, he decided his best chance to get to know Russia was to join the Foreign Service and become a diplomat.