The broader definition of perjury occurs under Section 1621, which defines the crime as any false declaration made under oath before a competent tribunal, officer, or person in any case in which a law of the United States authorizes an oath to be administered. Section 1623, on the other hand, defines perjury as sworn false statements made in any proceeding before or ancillary to any court or grand jury of the United States. Penalties under the two statutes also differ. Under some circumstances recantation of perjured testimony may preclude prosecution under Section 1623, but under Section 1621 recantation is not an accepted defense. Other defenses are also discussed. Elements of the offense as defined by both statutes are outlined, along with relevant case law and procedural issues. 125 footnotes.