Federal habeas corpus is a procedure under which a federal court may review the legality of an individual's incarceration. This section constitutes an overview on California habeas corpus practice as it relates to the handling of criminal appeals.A habeas petition proceeds as a civil action against the State agent (usually a warden) who holds the defendant in custody. A writ of habeas corpus is a legal order that requires the custodian to bring the detained individual before a court or judge. If you want information about federal habeas corpus, send a request to Prison Law Office, General Delivery, San. The Writ of Habeas Corpus protects prison inmates from false imprisonment to ensure people are not thrown into jail unlawfully. It's crucial to understand its role in the justice system. The "Great Writ" of habeas corpus is a fundamental right in the Constitution that protects against unlawful and indefinite imprisonment. The writ may also be employed in a wide variety of situations not involving criminal proceedings. Entitled "Petition for Writ of Habeas Corpus Re: Quarantine Detention " (attached form PB4052).