Animal farm is a political fable in the form of an allegory: it describes the revolt of the animals on a farm, who expel their cruel human master and resolve to run it themselves on Socialist principles.
According to the plot a wise aged boar, Old Major, is one of the animals working on Mr Jones's Manor Farm. One day he gathers all the animals of the farm in the barn to tell them of a dream he has had the night before. But, before speaking of his dream, he reminds them that all animal's lives are "miserable, laborious and short"; they are given insufficient food , and are obliges to work "to the last atom of their strength". But who condemns animals to this life of misery and slavery? Man, the real enemy they have on earth, who steal all the all produce of their labor. If animals can get rid of man, ghee will become masters of their produce and their lives. They must, therefore, "work night and day, body and soul, for the overthrown of the human race!".
He then tells them his dream, the dream of a farm where animals work and live happily together, without the control of man. Three nights later Old Major dies peacefully and his body is buried at the foot of the orchard. Soon after his death the socialism he had proposed is drastically altered. Three young pigs, Snowball, Napoleon and Squealer, take over the leadership ; they change the name of the farm to "Animal Farm", and reduce the principles of the new philosophy to Seven Commandments.
1) Whatever goes upon two legs is an enemy.
2) whatever goes upon four legs, or has wings, is a friend.
3) No animal shall wear clothes
4)No animal shall sleep in a bed with sheets
5)No animal shall drink alcohol in excess
6) No animal shall kill any other animal without a cause.
7) All animals are equal.
One night all the animals of the farm join in a hard battle , defeat Mr Jones and run him off the farm. At first Animal Farm prospers, and when Mr Jones tries to take back his land, the animals defeat him once and for all. As time passes, however, Napoleon and Snowball begin to struggle with each other to obtain the leadership, and Snowball the intelligent but too idealistic leader is eventually sent to exile. It is better to see that animals are open to the same ambitions as men in human civilized society. Napoleon takes on the leadership; further meetings will no longer be allowed. All Napoleon's opponents are punished with death; the story of the animals rebellion is re-written to make Snowball appear as a traitor and a villain. Napoleon and his supporters begin acting as human beings: they sleep in beds, drink alcohol and begin trading with the neighboring farmers. The pig, Squealer, who is Napoleon's propagandist tells everybody that Napoleon is a great leader, though the animals are now, as before the rebellion, hungry and overworked. Over the course of time the Seven Commandments are reduced to one: "All animals are equal, but some animals are more equal than others". The name "Animal Farm" is changed back to "Manor Farm"; Napoleon asks to dinner a neighboring farmer, Mr. Pilkington, who has finally come to accept the revolution, and other rich farmers , and declares that he will ally with them against the lower classes. A group of common animals, looking at the scene from the window, can no longer distinguish pigs from men.
The main themes of the novel may be summarized as follows:
1) the struggle between humans and animals, which stands for the struggle against any form of exploitation.
2) the danger of propaganda.
3) the danger of the personality cult.
4) easy manipulation of the "masses".