Rocko Jerome: Agent of S.H.I.E.L.D. Front on that. I dare you. I've got what it takes. Maybe you do, too. Go try out the rigorous entrance exam to see if you qualify. Purchase of an Acura not necessary.
S.H.I.E.L.D. (Supreme Headquarters, International Espionage, Law-Enforcement Division) is the Marvel Comics equivalent of U.N.C.L.E. (as in, The Man From...) or any number of heroic fictional organizations designed to defend the people from a villainous foe, usually also in a group with a clever name. In this case, HYDRA. Which is comparable to SMERSH, Quantum, Cobra (the 80's G.I.Joe was originally pitched as a version of S.H.I.E.L.D.), you get the gist. Spy-Fi was all the rage in the early sixties, so Stan and Company figured it would make for great comics. Especially if said organization existed in the same world as Spider-man, Thor, The Hulk, the X-Men, Iron Man, Captain America, the whole gang.
While most far out spy stories use the organization the main guy is part of as background material, S.H.I.E.L.D. stories would focus on the man in charge: born in Brooklyn, tough as nails, WWII vet Nick Fury. Beyond that, he already had some credentials with readers. There had been the WWII stories in Sgt.Fury And His Howling Commandos, allegedly published as part of a bet between Stan and the great Jack Kirby that Marvel could have a success even with a horribly stupid title. They did, so as a reward, Nick got modernized. First to somewhat lackluster results by Kirby (the rare disappointment from Jack), and then by Jim Steranko, who took not just Nick Fury but the comics medium itself boldly into a new state of consciousness. You can read about his sixties heyday here.
When I say modernized, mind you, I'm talking about stories created in the sixties. Which instead of dated actually look futuristic, thanks to comic book special effects being limited not by technology or budget constraints, but only by the imagination of artists. Fury was a dynamo, all about riding atomic powered motorcycles, psyching out the enemies with LMDs (Life Model Decoys, robots that look and act exactly like people), hanging out on the Helicarrier (like an aircraft carrying warship, only it flies thousands of miles above the Earth), and kicking ass in a sleek leather action suit. He meant business, and although he hobnobbed with superheroes, he never was one himself. A big part of those early stories was that he was a mortal man, sometimes painfully aware that he was past his physical prime.
Unfortunately, time wasn't kind to the concept. Since Marvel Comics continually take place in whatever passes for "present day" and it was such an instrumental aspect of Fury that he had been in WWII, there was a contrived explanation that there was this "Infinity Formula" Nick was taking so that he would effectively be immortal. Sort of takes the wind out of the whole concept, doesn't it? I guess if it was my dime I'd just say he fought in Desert Storm, then 15 years from now you could still just say "Iraq," but nobody asked me.
In the current crop of refreshingly great movies based on Marvel Comics, Nick is portrayed by Samuel L. Jackson. The name has changed a bit, he's now the head of Strategic Homeland Intervention Enforcement and Logistics Division. That's not the only difference. You might have noticed that Sam looks quite a bit different than the classic depiction (he's bald!), but the most important thing to the character is that he's cool. Mr.Jackson was a hell of a lot cooler back before he became a parody of himself, but it's hard to be tough on the guy who was Jules in Pulp Fiction, and he hasn't done anything stupid in his Iron Man movie cameos so far. So, what the hell.
The art on this page is by, top to bottom, Steranko, Bruce Timm, and Francesco Francavilla. Many more great interpretations can be found here.