Just have a few questions about the changing of leadership and the fall of the Soviet Union after Stalin died. Would appreciate if details were given.

What was the impact of Stalin's death on the Soviet system?

What caused the Sino-Soviet split?

And what I really want to know is what perestroika and glasnost were. I know they were policies of reform put in by Gorbachev, but just wanted more details about how they both functioned and why they failed or succeeded.

Thanks!