George Orwell published Animal Farm in 1945, but it was written just under two years earlier. The book is a critique of the Soviet Union under Josef Stalin, and of the abuse of political power in general. By 1940, socialists and other left-wing sympathizers around the world (including Orwell) had become disillusioned Stalin's communist dictatorship, as reports of Stalin's violent purges and the enormous human cost of collectivization reached the West. The Nazi-Soviet non-aggression pact was in many ways the last straw, and Orwell depicts this event in his book, when Napoleon agrees to sell timber to the humans, who in turn attack and destroy the windmill. Overall, Orwell's book is about unintended consequences and especially about the importance of protecting individual liberties. Both of these were very current themes in light of Stalin's rise to power, as well as that of other dictators like Hitler.
George Orwell had written this statement in the Ukrainian edition of Animal Farm (1945):
On my return from Spain I thought of exposing the Soviet myth in a story that could be easily understood by almost anyone and which could be easily translated into other languages. However, the actual details of the story did not come to me for some time until one day (I was then living in a small village) I saw a little boy, perhaps ten years old, driving a huge cart-horse along a narrow path, whipping it whenever it tried to turn. It struck me that if only such animals became aware of their strength we should have no power over them, and that men exploit animals in much the same way as the rich exploit the proletariat.
Viewed in a very narrow framework, it is certainly an allegory of the Soviet Union's cruel and barbaric nature in its totalitarian reign. However, the book has broader appeal as the character names do not have Russian names but are more universal such as names from French, German, and English origins. The socio-political scenario in which there is a great inequality in what people have and in the rights of those people should not be abridged as it will led to a revolution, which will lead to greater dissatisfaction.