Their gimmick for the new team was that its members would come from different countries around the world, and they would be given a little more personality than the original team. In the story, Professor X - distraught by the disappearance of the original X-Men members - recruits mutants from Russia, Kenya, Canada, Germany, and the southwest United States to help locate the original team. After the mission is completed, the original X-Men decide to pursue their own lives, leaving Cyclops as the only original member to help Professor X train the new team.
Right from the start, readers sensed that something was different. One of the new team members, the Native American mutant codenamed Thunderbird, was killed off during his second mission. Ororo Munroe, codenamed Storm, was no 'Invisible Girl' - her powers over the weather made her one of the most powerful women in comics. And Wolverine harbored a mysterious past and a bestial nature that would help make him one of the most popular characters in comic history.
The key to the new team's success was characterization, with a lot of melodrama on the side. After Len Wein set the scene, writer Chris Claremont climbed on board to write an incredible 16 years' worth of adventures. His writing took the band of mutants from the sewers beneath New York City to the Canadian wilderness to an Antarctic jungle to the farthest reaches of alien empires. And the team evolved while it did all that traveling, adding new members while the old ones left and the remaining ones worked through their own personal issues.
The first book to introduce the new and improved X-Men would be on this list even if one only considered the team's financial impact on the industry - the thousands of issues, cartoons, and merchandise items emblazoned with the likenesses of the X-Men have made many millions of dollars for Marvel. But that popularity is only possible because of the strength of the writing. The new X-Men series was the best of the 'superhero soap-opera' comics - it was a book in which a large group of superpowered beings dealt with a lot more than just beating up super-villains. The stories dealt with each the feelings the team members had about each other other, along with the racial prejudice that their differences brought out in the non-mutant people who hated them. There was plenty of action and sci-fi adventures to keep things interesting, but there was also a lot of the human drama that's made the team so widely popular among non-traditional comic fans, as well.
There are so many reasons why this series stands out it's hard to decide which one to write about first. Storm is without question the strongest female African-American role model in comics history. Shadowcat, a teenage girl who discovers she can walk through walls like a ghost, was barely introduced before she was made an important part of the series (in other words, no teen sidekicks need apply here). The brilliant use of foreign-born characters (especially the Russian codenamed Colossus) allowed the writers to comment on the good and the bad in American society, and also gave them an excuse to use the whole world as their stage.
And then there were the specific stories that made comic history. The introduction of Alpha Flight, the first all-Canadian superhero team (which would go on to star in its own spinoff title). The "Dark Phoenix" saga, which ended in the suicide of a major character, an unheard-of act in comics at the time. The "Days of Future Past" storyline, which pictured a hellish, freedomless future worse than anything Hollywood could show us. On their best days, Chris Claremont and John Byrne weren't writing comics; they were creating myths, and the stories put down on paper 20 years ago still have far-reaching effects on the Marvel Universe.
It seems almost natural that the X-Men came along around the same time as movies like Jaws and Star Wars. Just as those movies signaled the rise of the blockbuster era in Hollywood, the X-Men's resurgence signals a shift in the comics industry towards stories with more action, more drama, larger rewards if they win, greater consequences if they fail, and lots of form-fitting costumes on the main characters. Good or bad, the X-Men have changed the focus of the industry forever, mutating it into a business aware of just how much drama - and money - it can generate.