从网上刚下的第六版的原版。看版上没有人发过，就发上来。因为本人还没有看完，只扫过一遍，应该没有缺页现象。如有问题，请指正。

Economics is a study of mankind in the ordinary business of life.” So
wrote Alfred Marshall, the great 19th-century economist, in his textbook,
Principles of Economics. Although we have learned much about the economy
since Marshall’s time, this definition of economics is as true today as it
was in 1890, when the first edition of his text was published.
Why should you, as a student at the beginning of the 21st century, embark on
the study of economics? There are three reasons.
The first reason to study economics is that it will help you understand the
world in which you live. There are many questions about the economy that might
spark your curiosity. Why are apartments so hard to find in New York City? Why
do airlines charge less for a round-trip ticket if the traveler stays over a Saturday
night? Why is Johnny Depp paid so much to star in movies? Why are living standards
so meager in many African countries? Why do some countries have high
rates of inflation while others have stable prices? Why are jobs easy to find in
some years and hard to find in others? These are just a few of the questions that a
course in economics will help you answer.
The second reason to study economics is that it will make you a more astute
participant in the economy. As you go about your life, you make many economic
decisions. While you are a student, you decide how many years to stay in school.
Once you take a job, you decide how much of your income to spend, how much
to save, and how to invest your savings. Someday you may find yourself running
a small business or a large corporation, and you will decide what prices to charge
for your products. The insights developed in the coming chapters will give you
a new perspective on how best to make these decisions. Studying economics will
not by itself make you rich, but it will give you some tools that may help in that
endeavor.
The third reason to study economics is that it will give you a better understanding
of both the potential and the limits of economic policy. Economic questions
are always on the minds of policymakers in mayors’ offices, governors’ mansions,
and the White House. What are the burdens associated with alternative forms of
taxation? What are the effects of free trade with other countries? What is the best
way to protect the environment? How does a government budget deficit affect
the economy? As a voter, you help choose the policies that guide the allocation of
society’s resources. An understanding of economics will help you carry out that
responsibility. And who knows: Perhaps someday you will end up as one of those
policymakers yourself.
Thus, the principles of economics can be applied in many of life’s situations.
Whether the future finds you reading the newspaper, running a business, or sitting
in the Oval Office, you will be glad that you studied economics.
N. Gregory Mankiw
December 2010