Stan Lee wanted to call Marvel’s next new superhero team The Mutants, but publisher Martin Goodman objected that kids wouldn’t know what that meant.
So it became The Uncanny X-Men — “X” being a spooky kind of a letter that suggests mystery (and for once, I agree with Goodman).
I bought my copy of the first issue off the newsstand in 1964, along with Avengers No. 1. (the more exciting choice, because it was a team composed of five characters I already knew and loved).
The X-Men seemed to combine the teenaged appeal of Spider-Man with the bickering bombast of the Fantastic Four, featuring an icy teen instead of a fiery teen and a Beast instead of a Thing. I was surprised and somewhat disappointed to see that the Beast’s power was super-agility rather than the Thing’s and the Hulk’s super-strength.
The team’s central protagonist was clearly Cyclops, the brooding romantic underdog whose overwhelmingly powerful eye beams were also an impairment that alienated him from the world.
I should say “further alienated him,” because the concept of humanity’s distrust of the mutant heroes was built into the concept from the first.
The X-Men have a sui generis explanation for their super powers — mutation. They don't need radioactive spiders or exploding planets. They can easily exist in their own self-contained universe (although, like all the other Marvel superheroes, they didn’t).
It’s no coincidence that the first successful superhero team in the movies would be the X-Men, because the explanation for their powers has that appealing dramatic simplicity. It’s harder for audiences to accept a dozen different excuses for the characters’ super powers (the Avengers got that problem out of the way by spring-boarding from separate origin movies that established the characters).
Even the villain in that first issue would become a major Marvel icon. The title itself fared well under Jack Kirby and Stan Lee, then faltered in other hands.
A 1970s revamp and revival would propel it permanently into the stratosphere, helped along by a popular character who would anticipate the dark turn to come in comics. The superheroes were going to grow claws.