A more thorough explanation:

Reciprocal Discovery is a legal principle that requires the defendant in a criminal case to provide the prosecution with copies of any pretrial statements made by defense witnesses during the discovery process. This principle is also known as "reverse Jencks material."

For example, if a defense witness gave a statement to the defense team before trial, the defendant must provide a copy of that statement to the prosecution. This allows both sides to have access to all relevant information and evidence, which can help ensure a fair trial.

The principle of reciprocal discovery was established by the U.S. Supreme Court in the case of U.S. v. Novles. The Court emphasized that allowing the prosecution to obtain defense pretrial statements would "substantially enhance the search for truth." This means that by having access to all relevant information, both the prosecution and defense can better determine what actually happened and present their cases more effectively.

Reciprocal discovery is an important part of the criminal justice system because it helps ensure that all parties have access to the same information. This can help prevent wrongful convictions and ensure that justice is served.