U.S. Army Rangers- The three battalions of Rangers are commandos in the classic (World War II) sense. They are light infantry who are trained to perform many of the missions the Special Forces normally take care of (raids, pilot and equipment recovery) plus something the Special Forces normally avoids; light infantry operations (using a several dozen or more troops for an operation.) 

The Rangers are America's largest emergency response military unit (the smaller one is Delta Force) that are ready to fly off to an overseas trouble spot in less than 24 hours. One of the three Ranger battalions is always assigned to this duty (spending one month being ready go on 18 hours notice) and two months off (doing intensive training.) The 75th Ranger Regiment headquarters is at Fort Benning, Georgia. The 1st Battalion of the 75th Regiment (1/75) is stationed at Hunter Army Airfield, Georgia , the 2nd Battalion (2/75) is at Fort Lewis, Washington and the 3rd Battalion (3/75) is at Fort Benning, Georgia.

But "the Rangers" are more than the 75th Ranger Regiment. There is also the Ranger Training Brigade, which consists of three more ranger battalions (the 4th, 5th and 6th) who train those who which to join the ranger regiment as well those who are there just to become qualified as a ranger. This is an important distinction that is often misunderstood. There is a difference between those who are "tabbed Rangers" (authorized to wear the Ranger tab on their uniform) and those who are simply members of the 75th Ranger Regiment. Any physically fit infantryman (and troops in other job categories the Rangers need) can apply to join the 75th Ranger Regiment if they have already gone through parachute training ("jump school"). They will have to pass a physical fitness test first, as the standards at the 75th Ranger Regiment are very high and there's no point sending any volunteers if they are not up to the minimum requirements. The Rangers encourage promising new recruits to volunteer to try for Ranger duty from the beginning. That way, the new recruit goes to the two week jump school right after 14 weeks of basic and advanced infantry training and is ready to try out for the rangers. This involves the 26 day long RIP (Ranger Indoctrination Program). About 60 percent of the volunteers fail. Those who pass are now members of the 75th Ranger Regiment, but they are not "rangers." How can this be? 

Simple, the Ranger training was always meant to identify and train the elite infantry leaders. The purpose of Ranger School, for it's first 20 years (until the 1970s), was to try and provide one Ranger NCO per infantry platoon and one Ranger officer per infantry company. That goal proved impossible to attain. There just weren't enough qualified volunteers for the tough training. But young infantry officers, in particular, were encouraged to attend Ranger school. The Ranger tab helped ones promotion prospects enormously. Until the 1990s, Ranger School was open to anyone in the army who could pass the physical qualification test. In practice, the army wanted it's hotshot infantry officers and NCOs to attend and eventually anyone not working in, or directly with, the infantry, were not allowed to try out for the school. Even so, about 20 percent of attendees are from other services (marines, SEALs and air force special operations) and another 20 percent from foreign nations (many of which have their own Ranger schools, some of which are even harder to pass than the U.S. one.) 

The Ranger School is a 62 day course designed to identify and train elite infantry leaders. The training goes on for about 19 hours a day, seven days a week. The attrition rate is about 60 percent. The school emphasizes mastery of basic infantry skills and the ability to lead troops under stressful conditions. Students for Ranger School arrive wearing uniforms devoid of rank insignia. Everyone is of equal rank during the 61 days of training, with everyone taking turns leading squad size units of their fellow students in various exercises. The Ranger School program emphasizes resourcefulness, physical toughness and the ability to think clearly while under extreme stress (and lack of sleep.) 

Young soldiers who come into the 75th Ranger Regiment via jump school and the RIP, are allowed to attend Ranger School after they have served in the 75th Ranger Regiment for 6-12 months. Because of the heavy work load in the Rangers, few are allowed to serve in the 75th Ranger Regiment for more than 2-3 years. This goes back to the idea of the rangers as more of a training program than a combat unit. This makes sense, for if you see anyone wearing the Ranger tab, you know they have gone through an extremely tough and selective training program. So while the 75th Ranger Regiment is a tough combat unit, it's long term purpose is to produce effective combat leaders for the rest of the army, as well as a source of qualified recruits for the Special Forces and Delta Force. 

The ranger regiment actually hasn't seen much action since it's formation in 1974. But that has a lot to do with American political leaders reluctance to get involved in overseas military emergencies. And if such action is needed, using fewer troops (as in Delta Force, SEALs or Special Forces ) is preferred. The rangers are seen as the ultimate strategic reserve. So when there is something really, really important that can only be taken care of with several hundred very well trained infantry, the rangers are ready to go.