Many nations have specialist fighting units alongside their main land, sea and air forces. They are formed and trained to carry out military operations that go beyond what might be expected of conventional forces. This new book looks at a number of these forces including the UK's SAS, the US Navy SEALs and Russia's Special Forces Group. It analyses the selection and training process, the ideology behind their formation and the ways in which they are intended to be used - and have been used in combat - and their effectiveness in carrying out their missions.