Tax laws are rules by which public authorities can collect revenue from individuals and organizations. There are many different kinds of taxes, including income taxes, property taxes, sales taxes, and commodity taxes.

Different nations may have similar tax laws. In the United States, for example, a taxpayer's home state may impose income tax on a taxpayer who has earned income from a business in another state. This double taxation can be avoided through international treaties.

However, in some countries, the same authority cannot impose the same tax on a person twice. Instead, a public authority may require a taxpayer to transfer their income.

A tax law is a legal document that establishes a framework for collecting, administering, and enforcing taxes. The law is based on statutes and codes, and is often enacted by a legislature, executive, or judiciary.

When a public authority imposes a tax, it generally does so by transferring an interest in goods or services to the government. An income tax, for instance, is a tax on income, which is a transfer of the interest in a good or service.

Taxes are also levied on physical assets, transactions, and a variety of non-income sources. Many people, for example, are required to report their income on a federal income tax return.

In addition to taxes on income, the United States and other countries levy taxes on property and capital gains. A variety of items are considered property, and these include real estate, vehicles, jewelry, and artwork.