Defendant who petitions for writ of habeas corpus has a right to challenge the judge assigned to the petition when the matter is given to a judge other than the original trial judge. Maas, who was serving a life Three Strikes term, petitioned for writ of habeas corpus challenging the validity of his sentence and alleging ineffective assistance of trial counsel. He sent the superior court multiple requests to identify the judge assigned to his petition but the court failed to provide him that information. The case was assigned to Judge Thompson, who was not the original trial judge in Maas’ case. Thompson denied the petition. Maas filed a habeas petition in the Court of Appeal claiming the trial court improperly denied him the right to challenge the judge assigned to his petition (Pen. Code, § 170.6). Held: The petition was treated as seeking writ of mandate and granted. Section 170.6 permits a party to an action, including a writ petition, to disqualify an assigned judge based on the movant’s declaration the judge is prejudiced against the party or his attorney. A good faith belief that the judge is prejudiced is sufficient to require recusal. The right to assert a peremptory challenge under section 170.6 is a substantial one. It is an important component of California’s system of due process and should be liberally construed to allow the challenge. Here, Maas was improperly denied his right to challenge to Judge Thompson. The superior court was directed to vacate the order denying Maas’ petition and to assign the matter to a different judge. [Editor’s Note: If a habeas petition raising issues related to the petitioner’s criminal proceedings is assigned to the original trial judge, the petitioner may not exercise a section 170.6 challenge. (See Yokley v. Superior Court (1980) 108 Cal.App.3d 622.)]