The X-Men debuted in 1963 as a superhero team whose members happened to be teenagers. Having to make them evade parents and gather every issue would have been a pain, and some sort of adult mentor figure seemed appropriate, so it was off to boarding school. But the school aspect was kind of a joke: there were only five students and one teacher, and though Hank McCoy was occasionally spotted reading a math book, there seemed to be no classes. It was just a junior varsity superhero team, with masks and bright uniforms, who went on missions and fought "muha muha muha" supervillains.
One other thing: Stan Lee couldn't be bothered to come up with individual origins for every character so he declared them all "mutants" who'd just been born with their powers, which kicked in at puberty. This had the handy effect of supplying some motives other than "muha muha muha" for the supervillains ("I want to kill all the mutants!" "I'm a mutant and want to kill all the humans!") and gave the characters something to angst about. However, it was the exact same thing Spider-Man angsted about: having passersby mutter about how creepy you are as you are saving their lives. Otherwise, the mutant issue was window dressing.
Story-wise, these early X-Men comics are of purely historical interest. This was an adventure comic written for prepubescent boys, meant to be consumed in much the same way as a candy bar. You were ten years old, you saw a comic on a spinner rack at the drugstore and shelled out your twelve cents, and you got a dose of guys in yellow jumpsuits exchanging comic-book banter and kicking Magneto in the head. Maybe a few months later you'd get another one, or maybe you'd get a Pepsi instead; the stories didn't assume any long-term investment. Sure, some people followed the titles month after month to see how the subplots developed, but even among this group there was a lot of turnover: companies depended on a steady stream of eight-year-olds coming in to replace the fourteen-year-olds going out.
Thus, even more than on a contemporaneous TV show like "Gilligan's Island," early X-Men comics tended to repeat the same stuff over and over. Characters would ostentatiously refer to each other by name and demonstrate their powers and basic personalities in the first few pages. There might be a page of subplot that never went anywhere. (For instance, for about eight years Scott and Jean pined for each other in thought balloons but neither dared say anything. Same angst every issue.) There'd be a fight against one of the usual antagonists: Magneto, say, or the Sentinels. The same plot developments recurred over and over: "Oh no Professor X is leaving can we really fend for ourselves" was a popular one. Sure, he did it every couple of years so it wasn't exactly a novel experience, but most of the audience didn't know that. And readers who were longtime fans tended to enjoy the repetition, just as fans of a band like hearing their favorite songs at every show.
But The X-Men was kind of a flop, and though the last few issues of new material were marked by great art by Neal Adams, after #66 it went into reprints. It wasn't until 1975 that it came back, with a very different cast. Out went the five white American kids with their single token female; in came a German, a Soviet, an Irishman, a Japanese, a Kenyan, a Canadian, and an Apache. (Later a junior division was added, made up of a Brazilian, a Cheyenne, a Vietnamese, an Appalachian, and a Scot.) For a stretch of over fifteen years, this new generation of X-Men would be written by Chris Claremont, and it evolved into something quite different.
They still wore costumes, and still got into fights with bad guys. But Claremont's run was founded on a couple of observations about the premise Stan Lee had established. First: so, mutants are just regular kids who, when puberty hits, suddenly find themselves full of confusing feelings and new abilities they can't control? Gosh, who could relate to that? But the world of the X-Men was more than just an allegory for adolescence in general. Mutants were people, who, when puberty hit, discovered that they were different from their peers, and became outcasts.
The Uncanny X-Men, as the cover now declared it, became a smash hit and according to some saved the American comics industry. The audience was different now: fewer children, more teenagers, especially geeky ones. So it's no wonder the X-Men ruled the charts: though titles like The Avengers were basically stories about the triumph of the jocks, with he-men like Thor and Captain America beating up troublemakers, the X-Men's role in the Marvel Universe more closely resembled that which the readers held in their high schools. And Claremont wrote a comic in which the outcasts weren't just different from everyone else, but special, and while they may have been shunned by their families and by society in general, they found a surrogate family at the mansion.
Even in the 1960s there had been some hints in the direction of The X-Men as an allegory for the civil rights movement, with Professor X as Martin Luther King and Magneto as Malcolm X, but now gay rights became a large part of the subtext: "When I hit puberty I discovered I wasn't like the other kids and now everyone thinks I'm a crime against nature" isn't really about energy blasts. But it was more than just a gay-friendly book. The cultural diversity, as noted, was in-your-face (especially given that Claremont, one of the world's most mannered writers, insisted on giving everyone a distinct heavy accent peppered with foreign words). And to say that Claremont had a penchant for strong women is an understatement: Storm was considered a goddess from the get-go, Jean Grey was powered up to become the planet-ravaging Phoenix, and even those with less world-shaking powers were as tough as any of the guys — but they were still cute and nice and approachable and would probably be your friends if you lived in their world. And that was the big selling point of the book: camaraderie among outcasts. The X-Men played baseball, went shopping, cooked dinner, were there for each other in tough times.
The school angle remained the thinnest of fictions — most of the cast was well past school-age — but now they weren't a mutant GI Joe team either, going on missions to fight supervillains: X-Men plots tended to be a matter of the cast hanging around the mansion minding their own business and then getting attacked. The series still hit the same marks it had in the 1960s — the X-Men still fought Magneto, Sentinels still tried to kill them, Professor X still left and came back — but the genre had changed from adventure stories for children to melodrama for marginalized teenagers. Magneto went from a cackling villain to a misunderstood anti-hero. The Phoenix Saga, still widely considered the high point of the book, dealt with a friend running out of control. Even when the book turned to cinematic adventure, with the X-Men facing the alien Shi'ar and the spacefaring Starjammers, soapy elements predominated: Scott finds out the Starjammer leader is his father, Professor X becomes the mate of the Shi'ar empress.
Morrison had a few original ideas to toss into the mix, but he mostly cycled back through the same plots as those who had come before him. He had the Sentinels attack. He had Professor X leave and the Shi'ar show up. He had the X-Men fight Magneto for the billionth time. He even did his own Phoenix Saga. But he did it in a different genre from both Lee and Claremont.
Morrison approached the X-Men from the following angle: hey, for the first time in forty years, let's actually use the premise! No longer is the mutant idea just there to allow lazy writers to churn out new superheroes, or to make for a handy reason for characters to feel oppressed; New X-Men is a science fiction series about a world in which a new species is beginning to supplant humankind and, if projections are correct, will completely replace it in four generations. As Morrison has suggested in interviews, there's no need for the mutant idea to be allegorical to be interesting or relevant, not in a world where genetic engineering is no longer a sci-fi fantasy but a growing industry. New X-Men is also about a school — for the first time, Xavier's becomes an actual school, with a faculty made up of several of the 20th-century X-Men, and 152 teenage students who take academic classes along with those on mastering one's powers. They're not future superheroes — some of them are just freaks who happen to have multiple noses, or ultra-long limbs, or transparent skin made of wax. The characters don't wear costumes (except in the India office, where the Bollywood-raised populace loves them). They're not superheroes in the Captain America sense. They're just trying to prevent more genocide in a world that is freaking out about the end of the human race.
Morrison also wrote for a different audience from Lee's or Claremont's. Stan Lee wrote stories for kids with captions that sounded like the patter of a carnival barker and dialogue like a "Gilligan's Island" script. Chris Claremont wrote stories for teenagers with endless captions composed of thick purple prose and excruciatingly mannered dialogue. (If Claremont were writing a typical evening at my house it might go something like: "I am Adam! What, Jennifer, would you like for dinner?" "That, Adam, depends... / ...on what is in the fridge." "Perhaps, my love, I will go to the store and get some groceries, inshallah.") But by the 21st century, neither of these groups was likely to be reading the title. I'm a member of the last age cohort to get into comics as children via spinner racks in convenience stores and the like, and I'm thirty. Today's kids and teens, if they read comics, read manga. American comics are bought by adults. Smart adults — grown-up geeks. So that's who Morrison wrote for.
See, a problem that has always plagued superhero comics is that of stasis. Though there are some amazing writers on a few of the titles, these are still commercial properties they're writing. In the early days, characters' status quo changed enormously over time: characters grew up (Spider-Man went through high school almost in real time and then went off to college, for instance), their relationships with one another changed, as did their looks and powers... but then that all stopped. Marvel's core business is no longer comics; it's maintaining a stable of properties that can be turned into movies and toys. These properties have to stay recognizable. So if a writer dares to allow characters to grow, to overcome their problems — the hard-luck college guy ends a string of bad relationships and is happily married, the android develops human emotion, the villain goes straight, a character dies a noble death — someone else gets brought in and it's "back to basics!" Divorce the wife! Wipe the robot's memory! Make the reformed guy go bad again! Resurrect the dead chick!
What Morrison did was say, hell with it — whatever happened before, whatever happens after, I'm writing a book. His entire run, though divided into arcs, is one long story, with a beginning, a middle, and a beautiful Joycean ending. Bits foreshadowing the twists of his thirty-second issue are sprinkled into his fourth... many comics writers slip portentious pages of shadowy figures up to mysterious doings into their stories, but New X-Men offered the delicious pleasure of discovering clues that in retrospect could not be more obvious but at the time didn't even look like clues.
And this isn't form without content. Magneto had gone from cackling arch-enemy in The X-Men #1 to misunderstood anti-hero under Claremont; Morrison offered Magneto as a meditation on the power of the revolutionary as iconic image vs. the reality of the revolutionary as a flesh-and-blood creature. Under Lee, the school was a secret commando unit; in the 70s, it became a refuge; Morrison examined the school as an educational institution, asking how we balance the need to teach students to think critically and question authority with the need to keep them from questioning authority so much that the school ceases to function. Heady stuff.
Now Claremont is back, and a mandate has come down from the higher-ups that the X-Men are to become superheroes again and wear gaudy costumes and suchlike. Back to basics, y'know. But that's fine — it reinforces New X-Men as a stand-alone work, and a pretty damn impressive one.