This article needs additional citations for verification .(April 2008)
In common law legal systems, black-letter law refers to well-established legal rules that are no longer subject to reasonable dispute.  For example, it is "black-letter law" that the formation of a contract requires consideration, or that the registration of a trademark requires established use in the course of trade. Black-letter law can be contrasted with legal theory or unsettled legal issues.
In an 1831 case in the U.S. Supreme Court, Jackson ex dem. Bradstreet v. Huntington, the phrase "black letter" was used: "It is seldom that a case in our time savours so much of the black letter; but the course of decisions in New York renders it unavoidable...".  The phrase "black-letter law" was used in the Pennsylvania Supreme Court case Naglee v. Ingersoll, 7 Pa. 185 (1847). The phrase does not come from association with Black's Law Dictionary, which was first published in 1891. Instead, it refers to the practice of setting law books and citing legal precedents in blackletter type, a tradition that survived long after the switch to Roman and italic text for other printed works.
The phrase definitely refers to a distillation of the common law into general and accepted legal principles. This can be seen in the quote above from the Supreme Court where the court is noting that while the black letter law is clear, New York precedent deviates from the general principles.
In the common law, the informal notion of black letter law includes the basic principles of law generally accepted by the courts and/or embodied in the statutes of a particular jurisdiction. The letter of the law is its actual implementation, thereby demonstrating that black letter laws are those statutes, rules, acts, laws, provisions, etc. that are or have been written down, codified, or indicated somewhere in legal texts throughout history of specific state law. This is often the case for many precedents that have been set in the common law.
An example of such a state within the common law jurisdiction, and using the black letter legal doctrine is Canada. Canada is a monarchical state, with its roots invested in Colonial England,[ relevant? ] and black letter law is the principles of law accepted by the majority of judges in most provinces and territories.[ citation needed ] Sometimes it is referred to as "hornbook law" meaning treatise or textbook, often relied upon as authoritative, competent, and generally accepted in the field of Canadian law.
In lawyer lingo, hornbook law or black letter law is a fundamental and well-accepted legal principle that does not require any further explanation, since a hornbook is a primer of basics. Law is the rule which establish that a principle, provision, references, inference, observation, etc. may not require further explanation or clarification when the very nature of them shows that they are basic and elementary.
The phrase is nearly synonymous with the phrase "hornbook law". There are a number of venerable legal sources that distill the common law on various subjects known as Restatement of the Law. The specific titles will be "The Restatement (First) of Contracts" or "The Restatement of Agency" etc. Each of these volumes is divided into sections that begin with a text in boldface that summarizes a basic rule on an aspect of the law of contracts, agency etc. This "restatement" is followed by commentary and examples that expand on the principle stated.
Another synonymous term, usually used in the United Kingdom is "trite law".
In law, common law is the body of law created by judges and similar quasi-judicial tribunals by virtue of being stated in written opinions.
Constitutional law is a body of law which defines the role, powers, and structure of different entities within a state, namely, the executive, the parliament or legislature, and the judiciary; as well as the basic rights of citizens and, in federal countries such as the United States and Canada, the relationship between the central government and state, provincial, or territorial governments.
Jurisdiction is the legal term for the legal authority granted to a legal entity to enact justice. In federations like the United States, areas of jurisdiction apply to local, state, and federal levels.
A precedent is a principle or rule established in a previous legal case relevant to a court or other tribunal when deciding subsequent cases with similar issues or facts. Common-law legal systems often view precedent as binding or persuasive, while civil law systems do not. Common-law systems aim for similar facts to yield similar and predictable outcomes, and observing precedent when making decisions is the mechanism to achieve that goal. Common-law precedent is a third kind of law, on equal footing with statutory law and subordinate legislation in UK parlance – or regulatory law. The principle by which judges are bound to precedents is known as stare decisis.
Judicial independence is the concept that the judiciary should be independent from the other branches of government. That is, courts should not be subject to improper influence from the other branches of government or from private or partisan interests. Judicial independence is important for the idea of separation of powers.
In human interactions, good faith is a sincere intention to be fair, open, and honest, regardless of the outcome of the interaction. Some Latin phrases have lost their literal meaning over centuries, but that is not the case with bona fides, which is still widely used and interchangeable with its generally-accepted modern-day English translation of good faith. It is an important concept within law and business. The opposed concepts are bad faith, mala fides (duplicity) and perfidy (pretense). In contemporary English, the usage of bona fides is synonymous with credentials and identity. The phrase is sometimes used in job advertisements, and should not be confused with the bona fide occupational qualifications or the employer's good faith effort, as described below.
English law is the common law legal system of England and Wales, comprising mainly criminal law and civil law, each branch having its own courts and procedures.
Case law, also used interchangeably with common law, is law that is based on precedents, that is the judicial decisions from previous cases, rather than law based on constitutions, statutes, or regulations. Case law uses the detailed facts of a legal case that have been resolved by courts or similar tribunals. These past decisions are called "case law", or precedent. Stare decisis—a Latin phrase meaning "let the decision stand"—is the principle by which judges are bound to such past decisions, drawing on established judicial authority to formulate their positions.
The American Law Institute (ALI) is a research and advocacy group of judges, lawyers, and legal scholars established in 1923 to promote the clarification and simplification of United States common law and its adaptation to changing social needs. Members of ALI include law professors, practicing attorneys, judges and other professionals in the legal industry. ALI writes documents known as "treatises", which are summaries of state common law. Many courts and legislatures look to ALI's treatises as authoritative reference material concerning many legal issues. However, some legal experts and the late Supreme Court Justice Antonin Scalia, along with some conservative commentators, have voiced concern about ALI rewriting the law as they want it to be instead of as it is.
A brief is a written legal document used in various legal adversarial systems that is presented to a court arguing why one party to a particular case should prevail.
In the United States, state law refers to the law of each separate U.S. state.
In laws of equity, unjust enrichment occurs when one person is enriched at the expense of another in circumstances that the law sees as unjust. Where an individual is unjustly enriched, the law imposes an obligation upon the recipient to make restitution, subject to defences such as change of position. Liability for an unjust enrichment arises irrespective of wrongdoing on the part of the recipient. The concept of unjust enrichment can be traced to Roman law and the maxim that "no one should be benefited at another's expense": nemo locupletari potest aliena iactura or nemo locupletari debet cum aliena iactura.
Civil law is a legal system originating in mainland Europe and adopted in much of the world. The civil law system is intellectualized within the framework of Roman law, and with core principles codified into a referable system, which serves as the primary source of law. The civil law system is often contrasted with the common law system, which originated in medieval England. Whereas the civil law takes the form of legal codes, the law in common law systems historically came from uncodified case law that arose as a result of judicial decisions, recognising prior court decisions as legally-binding precedent.
In American jurisprudence, the Restatements of the Law are a set of treatises on legal subjects that seek to inform judges and lawyers about general principles of common law. There are now four series of Restatements, all published by the American Law Institute, an organization of judges, legal academics, and practitioners founded in 1923.
Ratio decidendi is a Latin phrase meaning "the reason" or "the rationale for the decision". The ratio decidendi is "the point in a case that determines the judgement" or "the principle that the case establishes".
International law, also known as "law of nations", refers to the body of rules which regulate the conduct of sovereign states in their relations with one another. Sources of international law include treaties, international customs, general widely recognized principles of law, the decisions of national and lower courts, and scholarly writings. They are the materials and processes out of which the rules and principles regulating the international community are developed. They have been influenced by a range of political and legal theories.
Codification of laws is a common practice in the Philippines. Many general areas of substantive law, such as criminal law, civil law and labor law are governed by legal codes.
In United States legal education, hornbooks are one-volume legal treatises, written primarily for law students on subjects typically covered by law school courses.
The law of the United States comprises many levels of codified and uncodified forms of law, of which the most important is the nation's Constitution, which prescribes the foundation of the federal government of the United States, as well as various civil liberties. The Constitution sets out the boundaries of federal law, which consists of Acts of Congress, treaties ratified by the Senate, regulations promulgated by the executive branch, and case law originating from the federal judiciary. The United States Code is the official compilation and codification of general and permanent federal statutory law.
Judicial interpretation is the way in which the judiciary construes the law, particularly constitutional documents, legislation and frequently used vocabulary. This is an important issue in some common law jurisdictions such as the United States, Australia and Canada, because the supreme courts of those nations can overturn laws made by their legislatures via a process called judicial review.