Perestroika, which means "restructuring" in the Russian language, was a series of changes to the economy of the Soviet Union. Soviet leader Mikhail Gorbachev started it in 1986. This happened only a few years before the Soviet Union fell apart into 15 countries. Many historians argue that it was a major reason that the Soviet Union fell apart. It happened at about the same time as Gorbachev's "glasnost" reforms, which made what the government did not as much of a secret.