An amicus brief is a document which is filed in a court by someone who is not directly related to the case under consideration. The most classic example of an amicus brief is a document filed by an advocacy group such as the American Civil Liberties Union. The additional information which is found in such a document can be useful for the judge evaluating the case, and it becomes part of the official case record. Many nations allow people or entities to file such documents with their courts.

The tradition of accepting amicus briefs comes from a larger concept, the amicus curiae, or “friend of the court.” A friend of the court may be interested in a case for various reasons, although he or she is not directly involved. For example, a court might be preparing to try a case related to online file sharing, an issue of great concern to many people. An amicus brief might be filed to discuss the larger ramifications of potential case outcomes, since these ramifications might not be brought up by the prosecution or defense during the course of a trial.

Amici curiae can do a variety of things in addition to filing an amicus brief. They can also contribute academic evaluation of various matters related to a case, and they may testify and in very rare cases contribute to closing oral arguments. Many advocacy organizations act as amici curiae, as do some concerned individuals. States and governments may also step in with amicus briefs if they believe that a case may impact them.

Once an amicus brief is filed with a court, the court can decide whether or not to accept it. Such a brief may be rejected for any number of reasons, in which case it is not part of the final court record of the case, and it will not be considered in deliberations. In some regions, briefs filed by other states or territories are automatically accepted, as are briefs from the national government. The brief typically includes a description of who is filing it, and why, since an amicus brief is generally filed out of a desire to protect one's interests.

In a high profile case, numerous amicus briefs may be filed, sometimes by opposing organizations or individuals. The court may also take advantage of the expert knowledge offered by amici curiae who may volunteer to review various materials related to the case. Like other aspects of legal procedure, an amicus brief follows a specific format and there are certain protocols which must be followed when filing such a document. If you are interested in filing an amicus brief, you should consult a qualified lawyer in your area.