Army Special Forces: Mission and History
US Army Rangers
Military.com
Mission:
The United States Army Special Forces have five primary missions: unconventional warfare (the original and most important mission of Special Forces), foreign internal defense, special reconnaissance, direct action, and counter-terrorism. Other duties include combat search and rescue (CSAR), counter-narcotics, counter-proliferation, hostage rescue, humanitarian assistance, humanitarian demining, information operations, peacekeeping, psychological operations, security assistance, and manhunts.Special Forces have the ability to be virtually everywhere at once; this guarantees that they are the first on the ground or already at a crisis location when trouble starts.
http://www.military.com/special-operations/army-special-forces-missions-and-history.html