Talcott Parsons (December 13, 1902 – May 8, 1979) was an American sociologist of the classical tradition, best known for his social action theory and structural functionalism. Parsons is considered one of the most influential figures in sociology in the 20th century. After earning a PhD in economics, he served on the faculty at Harvard University from 1927 to 1929. In 1930, he was among the first professors in its new sociology department. Later, he was instrumental in the establishment of the Department of Social Relations at Harvard.