"2001" is a story of evolution. Sometime in the distant past, someone or something nudged evolution by placing a monolith on Earth (presumably elsewhere throughout the universe as well). Evolution then enabled humankind to reach the moon's surface, where yet another monolith is found, one that signals the monolith placers that humankind has evolved that far. Now mankind, assisted by artificial intelligence (such as HAL), must dare to encounter the monolith placers. If successful, the next step in evolution--whatever it is--will be achieved.