Highly-trained and immensely skilled, the SAS are widely regarded as one of the best Special Forces units in the world. Their missions are uniquely diverse:counter-terrorist responses at home and abroad; deep penetration for reconnaissance and guiding air strikes; training and supporting indigenous forces; counter-insurgency in collaboration with U.S. Delta Force, SEAL Team Six, and other foreign Special Forces; mobile operations in support of conventional forces; targeting terrorist leaders and manhunting war criminals, to "direct action" raids. This book charts the changing organization and operational emphases of the regiment over the past twenty-five years, as well as its individual deployments and operations, including those planned but aborted and joint missions with other British and foreign units. It sheds light on the SAS's involvement in the Troubles of Northern Ireland, their operations in Iraq and Afghanistan, and the widespread use of the SAS in counter-terrorism and counterinsurgency operations since 9/11.