Animal Farm is about the dangers of Marxist teachings, using a farm as a metaphorical country. When the "glorious revolution" takes place, the animals (citizens) join in working hard to benefit all, thinking that their newly appointed co-equal leaders will implement laws that work in favor of all people equally. However, as time goes on, the pigs (new leaders) take more while working less, using military strength and the public fear of "returning to the old ways" to stay in power. The concept of equality becomes less important than the official government position; public executions of "sympathizers" help to quell rebellious feelings. Eventually, Marxist leadership becomes dictatorship, with a small selected class ruling over the working class through fear, brutality, and intimidation.
Published in 1945, Animal Farm, written by George Orwell (born Eric Arthur Blair in India, the son of a British civil servant posted to that British colony), is an allegory intended to indict those who subvert legitimate rebellion for their own, usually megalomaniacal purposes. Orwell himself had traveled a then-common path, rejecting the fascism that took hold of Germany, Italy, and Spain, while identifying with the socialist vision of a more egalitarian society. It was the subversion of legitimate revolution in Russia that inspired him to write his story of farm animals who conspire to overthrow the farmer who exploits them for his own aggrandizement. Once the farmer is overthrown, the animals set out to construct their own version of utopia -- a version inspired by the theories of Karl Marx and Friedrich Engels and, in a considerably more sinister vein, Vladimir Lenin -- only to see the political machinations of two of them destroy that vision.
Orwell populated his farm with different kinds of animals common to such a venue. At the top of this farm's pecking order are the pigs, and the most respected pig is Old Major, who inspires the other animals to undertake the rebellion that will free them from tyranny. Addressing the assembled animals as "comrades," a typical communist greeting, Major delivers what can only be described as the quintessential Marxist-Leninist monologue intended to sway the others to his vision of utopia:
Now, comrades, what is the nature of this life of ours? Let us face it: our lives are miserable, laborious, and short. We are born, we are given just so much food as will keep the breath in our bodies, and those of us who are capable of it are forced to work to the last atom of our strength; and the very instant that our usefulness has come to an end we are slaughtered with hideous cruelty. No animal in England knows the meaning of happiness or leisure after he is a year old. No animal in England is free. The life of an animal is misery and slavery: that is the plain truth. . . Is it not crystal clear, then, comrades, that all the evils of this life of ours spring from the tyranny of human beings? Only get rid of Man, and the produce of our labour would be our own. Almost overnight we could become rich and free. What then must we do? Why, work night and day, body and soul, for the overthrow of the human race!
Old Major's speech to the assembled animals is right out of the Marxist-Leninist lexicon, its exhortations to rise up against capitalist tyranny the battle cry of freedom to those so disposed. As with the real-life figure of Lenin, however, Old Major dies too soon to witness the fruition of his vision of a new, more just society. In the vacuum Old Major/ Lenin's death creates, a power struggle ensues that pits two revolutionaries of vastly different temperaments, Napoleon and Snowball, modeled after Joseph Stalin and, it is believed, Leon Trotsky, two actual figures in the period following Lenin's death when the Bolshevik Revolution remained mired in conflict and political division. The period of Stalin's rule, which ended with his death in 1953, remains one of the bloodiest in modern history, rivaled only by Mao Tse-tung's China and Hitler's Germany.
The main theme of Animal Farm, then, is the subversion of legitimate revolution and its replacement with the imposition of a totalitarian regime considerably worse than that which it replaced. Just as Stalin emerged triumphant in the post-Revolution Soviet Union, so does Napoleon defeat his rival, Snowball, in his bid for ultimate power. Animal Farm is an indictment of Stalinism, with animals serving as substitutes for the human beings whose greed and hunger for power come at the expense of the weak and exploited. The Stalinist Napoleon is far more ruthless and calculating than the Trotskyist Snowball, the latter being the more intellectual of the two. Orwell suggested that in the end, power trumps reason and theory.
Animal Farm is usually described as being a book about communism, its strengths and weaknesses. If you consider the animals to have human nature, it is clear in the book that complete equality is impossible because there are always animals (people) that will take advantage of the system to come out ahead of others. The book is about animals, but it asks the reader to see the barnyard as if it were a world filled with people.