What were the primary causes for the collapse of communism in Eastern Europe (Poland, Germany, Czechoslovakia, Hungary, Romania, etc) in 1989, and the USSR (Russia, Ukraine, Belarus, Georgia, etc) in 1991(focus on internal causes)? What was glasnost' , perestroika, and demokratizatsiia? Why did Mikhail Gorbachev and his supporters launch these policies in the former USSR in the late 1980s and what was the link between them and the collapse of the USSR and E. Europe communism? What was the Sinatra Doctrine? Why was life under post-communism so difficult in the former communist states in the 1990s?