The defendant is entitled to “Discovery”. Discovery is a process that allows the parties to learn the strengths and weaknesses of each other’s case by, for example, obtaining the names and statements of witnesses the other side intends to call at trial. Because the defendant in a criminal case has certain constitutional safeguards (such as the right against self-incrimination), discovery in criminal cases is far more limited than in the civil context.
In most states, the defense’s discovery power is much broader than the prosecution’s. Some states, including California, have enacted reciprocal discovery laws, which allow the prosecution to ask the same questions of the defense. In all jurisdictions, however, the prosecution is required to produce all exculpatory material (that which is favorable to the defendant or tends to negate his or her guilt).