Kids DefinitionKids; Legal DefinitionLegal; More from MW. The "Great Writ" of habeas corpus is a fundamental right in the Constitution that protects against unlawful and indefinite imprisonment.Habeas corpus or the "Great Writ" is a legal procedure that allows an individual in custody to challenge unlawful imprisonment or indefinite detention. A writ of habeas corpus requires that a person who is in custody be brought before a judge or court and that they be able to challenge that custody. Habeas Corpus, in the Federal Court, is a petition that claims that you are being detained against your US constitutional rights. A Writ of Habeas Corpus is a civil proceeding that is available in both State and Federal Court to challenge the legality of imprisonment. Superior Court of Orange County Website: The court provides a variety of online services. A petition for writ of habeas corpus. I ask unanimous consent that this val- uable article, entitled "The Colorado. River: From Its Sources to the Sea," be printed in the RECORD.