Mikhail Gorbachev: The last leader of the Soviet Union who implemented reforms such as glasnost (openness) and perestroika (restructuring) in an attempt to revitalize the country's economy.
Boris Yeltsin: The first president of Russia after it gained independence from the USSR. He played a crucial role during its transition period.
Dissolution: Refers to when something formally comes to an end or breaks apart, often due to internal or external factors.