Every Dictator of the Soviet Union Explained

Over the 69 years of the Soviet Union's existence, eight men officially stood at the apex of its political system. Arising from the brutal and sometimes murderous intrigues of Soviet politics, they led the Communist superpower as dictators until death or a coup removed them from their position.

But who were these men, whose terms in power ranged from decades to only a few weeks? What was their official position called?