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 New York, the discovery process in civil litigation is governed by the New York Civil Practice Law and Rules (CPLR). This process allows parties to obtain evidence from each other or from third parties to prepare for trial. The types of discovery tools available include depositions, interrogatories, requests for production of documents and things, examinations before trial (EBTs), and requests for admissions. Parties may also be required to make initial disclosures without a formal discovery request. The scope of discovery in New York is broad, permitting parties to obtain any material that is 'material and necessary' to the defense or prosecution of an action, as long as it is not privileged or unduly burdensome. The CPLR also sets forth the rules and deadlines for responding to discovery requests, and outlines the consequences for failing to comply, which can include sanctions. Additionally, parties may assert various privileges, such as attorney-client privilege or work-product protection, to withhold certain information from discovery. It is important for parties to adhere to the CPLR and any applicable local court rules to ensure a smooth discovery process.