As the supreme law of the U.S., the Constitution provides the framework governing all other law. It details how government is structured, how much authority it should have, what laws it can pass, and what rights belong to each citizen. Historically, amendments have been made to add important principles to the Constitution, such as freedom of expression and the more controversial right to bear arms.
Statutory laws are those created by the legislature, which is all the bodies with authority to pass laws. They include Congress at federal level and state legislature at state level. Democratically elected members propose laws or amendments to existing laws, and other members vote to pass or reject. The Constitution remains the main law by which all others should be judged. In cases where federal laws conflict with state laws, federal law always comes first.
In "Introduction to Law," Beth Walston-Dunham names judicial and administrative as the two other main areas of law in the U.S. In judicial law, a judge decides how a law should be applied to a certain case. This can create a precedent, whereby similar cases are decided in the same way in the future. Administrative law applies only to certain groups or areas, such as members of a particular industry. Laws set by the Federal Aviation Administration (FAA), for example, apply to commercial and private flying.