A basic purpose of law in our society is to maintain order and to resolve disputes. In this connection we must bear in mind that law is not simply a set of rules of conduct. It is also the means to impose responsibility and to enforce social justice

Law has also been defined as a command from a superior to an inferior. The tax law fits in well with this concept of law.
Law is also a method of social control. The law brings about changes in our society and society brings about changes in the law. In this sense law is both an instrument of change and a result of changes.
Laws can be classified in many ways too. Laws are sometimes referred to as substan-tive or procedural.6Substantive law defines rights, and procedural law establishes the procedures by which rights are protected and enforced.
Law is also frequently classified into areas of public and private law. Public law includes laws that affect the public generally. It can be further divided into constitutional law, administrative law and criminal law. Private law deals with the relationships between individuals in an organized society. It covers contracts, torts and property, each of which can be subdivided into several subjects.
The phrase sources of law is used here to describe methods and procedures by which law is created and developed. American law comes from four basic sources • constitutions, legislation, judicial decisions，and administrative rules and regulations.
Judicial decisions as part of law is a unique characteristic of American law. This concept of decided cases as a source of law is often referred to as the common law system, which must be contrasted with the civil law system developed in continental Europe.The civil law countries have codified their law so that the main source of law in those countries is to be found in the statutes rather than in the cases.9 Under the common law system, statutes as well as cases are sources of law.

Answer the following questions ： 1. What are the purposes or functions of law?
2. Are laws just a set of rules of conduct? Why or why not?
3. What is substantive law?
4. What is procedural law?
5. What is public law?
6. What is private law?
7. Give the names of laws that are defined according to their sources.
8. Name one unique feature of the American legal system.
9. What is a common law country?
10. What is a civil law country? Name as many civil law countries as you can.
11. Classify and describe the following laws in as many ways as you cans contractsf torts, property, criminal law，constitutionsf criminal procedure» civil procedure, legislation, administrative law* case law