A party may direct written interrogatories to any other party. A copy of the interrogatories shall be served on all other parties entitled to notice.A Practice Note discussing the structure and content of interrogatories in Illinois circuit court civil litigation under Illinois Supreme Court Rule 213. A sample response to interrogatories that may be used in discovery in Illinois circuit court litigation. Interrogatories are written questions that one party sends to the other. The receiving party is required to answer these questions under oath. Marital Interrogatories (requests the other party to answer questions) (see Illinois Supreme Court Rule 213). The court may grant a motion for the appointment of a master in a civil action where the parties stipulate in writing to such an appointment.