The importance of close air support (CAS) has markedly increased over the last five years in Operations Enduring Freedom and Iraqi Freedom. Ground forces have increasingly relied on the effects that airpower provides and will continue to do so in the foreseeable future. This has occurred while CAS doctrine and execution has undergone radical changes. While the fundamentals of a serviceman with a radio calling in air support have remained relatively constant since World War II, the level of mission complexity has steadily increased. Digital communications, precision guided munitions, collateral damage considerations, effects based operations and a joint battlefield have placed increased requirements on terminal attack controllers and CAS aircrew.