Most laws and legal systems—at least in the Western world—are quite similar in their essential themes, arising from similar values and similar social, economic, and political conditions, and they typically differ less in their substantive content than in their jargon and procedures. Communication between legal systems is the focus of legal translation and legal lexicography, which deals with the principles of producing a law dictionary.
One of the fundamental similarities across different legal systems is that, to be of general approval and observation, a law has to appear to be public, effective, and legitimate, in the sense that it has to be available to the knowledge of the citizen in common places or means, it needs to contain instruments to grant its application, and it has to be issued under given formal procedures from a recognized authority.
In the context of most legal systems, laws are enacted through the processes of constitutional charter, constitutional amendment, legislation, executive order, rulemaking, and adjudication; within Common law jurisdictions, rulings by judges are an important additional source of legal rules.
However, de facto laws also come into existence through custom and tradition. (See generally Consuetudinary law; Anarchist law.)
Law has an anthropological dimension. In order to have a culture of law, people must dwell in a society where a government exists whose authority is hard to evade and generally recognised as legitimate. People forego personal revenge or self-help and choose instead to take their grievances before the government and its agents, who arbitrate disputes and enforce penalties.
This behaviour is contrasted with the culture of honor, where respect for persons and groups stems from fear of the disproportionate revenge they may exact if their person, property, or prerogatives are not respected. Cultures of law must be maintained. They can be eroded by declining respect for the law, achieved either by weak government unable to wield its authority, or by burdensome restrictions that attempt to forbid behaviour prevalent in the culture or in some subculture of the society. When a culture of law declines, there is a possibility that an undesirable culture of honor will arise in its place.
A particular society or community adopts a specific set of laws to regulate the behavior of its own members, to order life in its political territory, to grant or acknowledge the rights and privileges of its citizens and other people who may come under the jurisdiction of its courts, and to resolve disputes.
There are several distinct laws and legal traditions, and each jurisdiction has its own set of laws and its own legal system. Individually codified laws are known as statutes, and the collective body of laws relating to one subject or emanating from one source are usually identified by specific reference. (E.g., Roman law, Common law, and Criminal law.)
Moreover, the several different levels of government each produce their own laws, though the extent to which law is centralized varies. Thus, at any one place there can be conflicting laws in force at the local, regional, state, national, or international levels.