Interrogatories are one form of discovery in a lawsuit. An interrogatory is a written question from one party to the lawsuit to another party to the lawsuit.Any party may serve written interrogatories directed to any other party. The Maryland Rules have form interrogatories that you can use as an example. Interrogatories are formal questions in writing to the adverse party requiring written responses under oath. All parties are limited to 30 interrogatories (written questions) sent to any other one party in the case. Interrogatories are written questions that require written answers under oath. Form No. 3 - General Interrogatories. 1. Maryland Rule 2-421 governs the manner in which Maryland personal injury attorneys may ask and answer interrogatories. In these interrogatories, the following definitions apply: (a).