Animal Farm is an allegory (a story with a moral message) about the Communist Revolution in the Soviet Union and its consequences. It is a critical fable that condemns the misuse of political power. It can be read as a simple story about animals or as a savage attack on the cruelties that occurred during and after the Bolshevik revolution in 1917 and continued to the 1940s. George Orwell's book condemns the idea of a "classless society" the animals (and Soviets) claimed to have created. For example, the pigs soon take over the "revolution" and soon the apples and milk are missing--presumably consumed by the pigs. By the end of the novel, the pigs are standing on their hind legs like humans and the animals can't tell the difference between pigs and people. His also satirizes the tyranny and totalitarianism that developed after the revolution. The sheep, representing humans, blindly follow the crowd and believe in the propaganda that Squealer (and the Russian state) created. Truth becomes whatever Squealer says it is, even if historical facts have to be changed. The Soviets also manipulated the facts of history to gain support of public opinion. In the novel, several of the original commandments are changed and the animals are led to believe real events did not happen. Orwell was so successful in his political satire that the book has never been out of print since it was published.