Before trial begins, the parties use procedural devices to obtain information and gather evidence about the case. The process of obtaining information from the opposing party or from witnesses prior to trial is known as discovery, which includes gaining access to witnesses, documents, records, and other types of evidence.
Generally, only information that is relevant to the case at hand is discoverable.
Discovery prevents surprises by giving both parties access to evidence that might otherwise be hidden. Discovery also serves to narrow the issues so that trial time is spent on the main questions of the case.