Law is a system of rules a society or government sets up to govern its members and their interactions with one another. The laws are enforced by police or courts, and people who break them face penalties such as fines. In ancient societies, leaders wrote laws to set out the rules for people to live by. Today, most countries have a constitution for the overall framework of society and make more laws to deal with specific matters. Laws can cover a wide range of activities, from the right to vote or own property to the treatment of animals.

Laws may be written by the people who govern a country, either directly or through elected representatives (e.g. parliament or congress). They can also be enacted by government agencies, such as a regulatory body or the military. The highest authority that makes the rules for a nation is usually called a supreme court. There are different systems of law around the world, including common law and civil law.

Some laws are based on religion, such as Jewish Halakhah or Islamic Sharia. Other laws are based on historical experience, such as the Code of Hammurabi. The way that a person is treated under the law may depend on their wealth and status, or whether they belong to a certain social group or gender. The laws of a country may also be influenced by cultural, ethnic or religious beliefs.

The guiding principles of the rule of law are that all people are equal before the law and that government is transparent, accountable and trustworthy. In the US, the Constitution lays out the checks and balances between the executive, legislative and judicial branches of government, to ensure that no one individual or group has total control over the law. The legal system must also be open and accessible to the public, so that people can understand what the law is and why it was made.

Law is a complex subject. There are many different opinions about what the law should be and what it means to be a good citizen. Some of these ideas are reflected in books about the law and in debates over legal topics. While there is no definitive definition of the law, a broad consensus exists that laws should be clear and consistent, and they should not discriminate against any person or group. Ultimately, the laws must reflect the needs of the time and place in which they are made. In other words, they must be “responsive to the felt necessities of the community, to the prevalent moral and political theories, to the intuitions of public policy, avowed or unconscious.” (James Madison, Federalist Papers No. 10, September 1787).