It is a metaphor for the humans' place in the universe

Rating: 10/10 (20 February 2011)

The movie is challenging to the mind. It is not about space flights. All parts of the movie are one story, one big picture. I would say it is about programming. The "so called monolith" is not a material thing, it is a program. It is like a universal programming rule: something is programming A, A is programming B  R is programming our SUN, SUN is programming humans, humans are programming HAL. The objects are programmed in order to complete a task. Once the task completed (or the programmed object is becoming dangerous to the programmer) the object is discarded. If you have a curious mind, you will find in this movie very important principles that human's program is based on; like complex patterns of 0 (avoiding suffering) and 1 (achieving pleasure), need for self expansion and achieving a goal. Interestingly, Kubrick emphasized the correlation between the humans program and space objects of the solar system, especially Moon (subconscious everyday life reactions) and Jupiter (expansion). EVERY detail in this movie has a meaning.
Kubrick intentionally used quite a lot of visual and sound effects affecting human's brain and not in a subtle way. That's why some people are complaining about noises and "LSD-induced images" while others are loving the movie even though most o them have no idea what it is about.