An Illinois Subpoena For Deposition is a court order issued by a judge to compel someone to appear in court to give testimony in a civil or criminal trial. This type of subpoena is used to gather evidence for a case, as well as to compel persons to appear in court, even if they are not a party to the case. There are two types of Illinois Subpoena For Deposition: a Discovery Subpoena and a Witness Subpoena. A Discovery Subpoena is used to compel the production of documents or other tangible evidence, such as computer records or emails. A Witness Subpoena is used to compel the appearance of a witness to give testimony at trial. In both cases, the person receiving the subpoena must appear in court on the date and time specified in the subpoena. Failure to comply with the subpoena can result in the person being held in contempt of court.