An Illinois Subpoena/Subpoena Ducks Cecum is a court order that requires a person or organization to appear in court and produce documents or other tangible evidence for use in a legal proceeding. It is issued by a court of law and may be issued to both individuals and businesses. There are two types of Illinois Subpoena/Subpoena Ducks Cecum: a Subpoena Ducks Cecum and a Subpoena Ad Testificandum. A Subpoena Ducks Cecum is a court order commanding a person or organization to appear in court and bring specified documents or other tangible evidence with them. A Subpoena Ad Testificandum is a court order commanding a person or organization to appear in court and testify under oath or affirmation. Both of these types of Illinois Subpoena/Subpoena Ducks Cecum must be served on the person or organization in question before they can be enforced.