Communism: government has final say over most or all aspects of the economy, controls media, and limits the upper class and redistribute wealth to the lower classes so that all aspects of the nation may prosper. The ideology that the needs of the Nation surpass the needs of the people and definitely the needs of the individual because if the Nation prospers, the people follow behind and reap the benefits.
Very good sounding on paper, not so great in practice because people are not very good at limiting their ambition. So, the top tier of society eventually fizzles out because no matter how much more work they do, they can only get X amount of the benefits. Anything over that goes back to the Nation and the lower class. So why would they decide to continue to work so hard? They don't (except by denial of free will) and therein lies the problem with pure communism. It does not work simply because of the human factor.
That is why in the modern world we have the "communist" nations of China and Russia that would more accurately be described as "socialist-communist" nations. They have been forced from the far end of the spectrum more toward the Centre because some aspects of free trade and capitalism are necessary to keep the economy on track. Likewise, many western nations are leaning toward policies of more government intervention in the economy because it stabilizes the otherwise uncontrollable and unforseeable fluctuations. This is what we see in the world today, the polar capitalists nations and the polar communists ones find themselves drifting toward more moderate policies because extremes do not produce long term fruits.