The setting of the story is essential to Orwell's approach. By using a farm, he is able to create a powerful allegory for utopian projects as a whole. One of the many strengths of allegory as a method of social criticism is that it allows readers to draw their own conclusions and make their own associations, which are the more powerful for it. Orwell never specifically compares Napoleon to Stalin, or Snowball to Trotsky, or even Animal Farm to the Soviet Union. The reader does that for themselves. So by choosing a farm as the setting for a "fairy story," as Orwell self-deprecatingly called his book, the author is able to demonstrate the complexities and dangers of ceding too much power to those in positions of authority, even if the motives for doing so are noble. For a book with such a weighty and frankly pessimistic message, Animal Farm does not read as preachy or moralistic, and this is a result of the book's setting. It can be read on a number of different levels, which helps to explain its enduring popularity.