Discovery is the factfinding process in civil litigation in which the parties to a lawsuit exchange requests for the production of documents and other tangible items (requests for production); written questions to be answered under oath (interrogatories); witness testimony to be provided by oral deposition; disclosures that may be required under the applicable rules without request from an opposing party; and requests or subpoenas to third-parties (who are not parties to the lawsuit) for the production of documents or tangible things, or the giving of testimony by oral deposition, for example.

The discovery process is one of the most important, time-consuming, and often expensive parts of civil litigation. The discovery process—including the scope of discovery requests, deadlines to respond, and privileges from responding—are usually governed by the state or jurisdiction’s rules of civil procedure or code of civil procedure. For example, in federal court discovery is governed by the Federal Rules of Civil Procedure.

In Michigan, the discovery process in civil litigation is governed by the Michigan Court Rules, particularly those found in Chapter 2 - Civil Procedure. These rules outline the methods and scope of discovery, including requests for production of documents, interrogatories, depositions, and required disclosures. Parties may request relevant information that is not privileged and is reasonably calculated to lead to the discovery of admissible evidence. The rules also set forth the time frames for responding to discovery requests and the consequences for failing to comply. Discovery can be conducted with parties to the lawsuit as well as third parties through subpoenas. The process is designed to ensure that both sides have access to the necessary information to prepare their cases, but it must be conducted in a manner that avoids undue burden or expense. Michigan's discovery rules align with the purpose of the Federal Rules of Civil Procedure to promote the just, speedy, and inexpensive determination of every action.