Robin and I like to think that we wrote this book with Orwell's injunction in mind. We wanted to write a different sort of book, one that gives as much attention to the task of making sure the student understands how economic models apply to the real world as it gives to the models themselves. We wanted to adpt Orwell's principle to the writing of an economics textbook:to let the purpose of economics to achieve a deeper understanding of the world-rather than the mechanics of economics dictate the writing