An Illinois Subpoena For Deposition is a document issued by a court to require a witness to appear and give testimony in a deposition. The deposition is typically taken before a court proceeding, such as a trial or hearing. The deposition is taken to obtain evidence or testimony from a witness. There are two types of Illinois Subpoena For Deposition: a Subpoena Ducks Cecum and a Subpoena Ad Testificandum. The Subpoena Ducks Cecum requires a witness to produce physical evidence such as documents or other tangible items to the court. The Subpoena Ad Testificandum requires a witness to appear and testify in court or in a deposition. Both types of Subpoena must be served on the witness in accordance with the Illinois Rules of Civil Procedure.