Glad to help explain. Short version is:
The *Green Berets* so-called by virtue of the dress uniform hat rarely [but sometimes!] worn on field operations gave the name to soldiers of the US Army's Special Forces branch, formerly a part of the Infantry, and still closely aligned with that field of soldiering. The SF role is often that of military advisor or teacher/instructor, often with foreign troops. Sometimes, direct action missions require SF techniques or talents, oftel linguistic or intelligence community-related.
The Rangers are Infantry and Airborne [paratroops] first, raising the procedures and skills of those functions to near-Olympic competitor levels. Often those from Airborne and/or Ranger units attempt the Special Forces [SF] entrance examinations, and often have some advantage over other applicants...and sometimes, not so much.
SF Operational Detatchment *Delta*, aka *the Delta Force* [and going by a couple of other designations [some classified, some not] over different time periods, is a relatively small special operations tasked unit within Special Forces, operational since approximately the failed *Operation Eagle Claw* hostage rescue attempt at the US Embassy in Iran, about which see this
So, yep, Delta, is part of the Special Forces, aka *the Green Berets.* The Rangers, very highly trained Infantrymen, are themselves very effective special forces capable units, and the Ranger-trained individuals not assigned to Ranger-designated units take their training and leadership back to other Army units and thereby increase the efficiency and capabilities of those units. And, sometimes, from there, they give a Special Forces qualification a try.
It's recently been possible to enlist directly for Ranger training, or for a try at the Special Forces *Q* qualification course; but that was not always so, and attempting to do so does not at all guarantee successful completion of that training.
Very interesting, thank you, Archy!
So the Delta Force soldiers are technically part of the Army Special Forces (Green Berets,) but are an elite unit within, same as SEAL Team Six is an elite unit within the SEALs?
Now, where do the paramilitary intelligence soldiers fit in, like Johnny Spann (God rest his soul) in the S.A.D., are they Special Forces also, like Delta and the Green Berets, or are they actually not soldiers, but more intelligence agents?
Thanks, Archy, I appreciate your answer on this stuff! I also religiously read you and Matt Bracken!
Ed