This chapter examines issues surrounding evidence disclosure and discovery in common law jurisdictions, focusing primarily on the disclosure regimes in England and Wales and in the United States. It first traces the evolution of pretrial evidence disclosure rules and provides an overview of common law approaches to disclosure obligations. In particular, it considers three kinds of evidence: evidence that the prosecution plans to present at trial to prove the defendant’s guilt, government evidence that does not favor the prosecution’s case, and evidence in possession of the defense that it plans to present at trial. The article proceeds by discussing the rationales and structural choices that adversarial justice systems are required to make in their disclosure schemes. One such choice is how much to empower judges, rather than the parties, to make decisions about disclosure requirements.