The novella is about animals on a farm that free themselves from their human masters. At first they work hard, have equality and are happy. Soon, different classes form (pigs, dogs, the rest) and the farm takes on a communist flavour. From here on, Orwell takes the reader on a complete transition of the farm from freedom to communism to communist-dictatorship. Since Orwell is using animals (instead of humans) he can create classes and gets away with some brilliant analogies. The book is tiny and takes only a few hours. Must read.