Rule 7(f) of the Federal Rules of Criminal Procedure provides for a bill of particulars upon motion to be made before the arraignment or within 10 days after arraignment of upon motion made with the permission of the court at any later time. However, the ordering of a bill of particulars is at all times at the court's discretion. The bill of particulars can be used as a tool for discovering and possibly for freezing the theory of the prosecution's case, although variance of proof from the bill is unlikely to be deemed reversible error unless a showing of actual prejudice or suprise is made. Rule 16 of the Federal Rules of Criminal Procedure defines the minimal discovery to which the parties are entitled by setting out the rights of both the defendant and the Government. Rule 16 does not affect the protections afforded attorneys' work products, however. The Brady rule recognizes a defendant's constitutional right to be given, upon request, all incriminating evidence possessed by the Government, although the time when the disclosure is to be made is not specified. Defendants and the Government have also tried to use information from civil proceedings of administrative agencies for discovery in criminal cases. The Freedom of Information Act also narrowly expands the discovery rights of criminal defendants. Motions that must be made prior to trial include attacks on the institution of the prosecution, claims of defect in the indictment or information, motions to suppress evidence, rule 16 motions, and severance motions. The court has broad discretion under rule 14 of the Federal Rules of Criminal Procedure and may order separate trials of counts, grant a severance, or provide whatever other relief justice requires. The broad range of possible pretrial motions to dismiss is limited only by existing case law and counsel's ingenuity. Common bases for these motions include delay in prosecution, duplicity, deficient indictments, and prosecutorial misconduct. Motions to suppress may be based on such grounds as illegal search and seizure and fifth amendment rights. Motions to suppress usually result in an evidentiary hearing, which provides an opportunity for discovery. Footnotes with references are provided. For related material, see NCJ 78913.