"Despite his advanced age, he always went to work, and was a real workaholic," his colleagues at the Levada center said.
Ukrainian-born Levada graduated from Moscow State University, and later became a professor of philosophy.
In the 1960s, he lectured in sociology at the university's journalism department, but lost his post in 1969 over what was termed "ideological discrepancies", and was banned from trips abroad for 20 years.
Levada continued to secretly organize workshops for like-minded academics.
During the perestroika period, Levada led the theoretical department at the newly-formed Public Opinion Research Center, and was later promoted to the head of the organization.
The center ran a special program for studies of public opinion changes in response to economic and social upheavals. The government, however, decided to transform the center into a joint stock company and gain control over it in 2003. Levada was fired without official explanation.
Levada's colleagues subsequently tendered their resignations, and opened an analytical public opinion think tank, Levada Center, in 2004.
