The X-Men is a superhero team in the Marvel Comics Universe and was created by writer Stan Lee and artist Jack Kirby and first appeared in The X-Men #1 (September 1963). Under a cloud of rising anti-mutant sentiment, Professor Xavier converted his Westchester mansion into a school and safe sanctuary for young mutants to train in their powers. He recruited Cyclops, Iceman, Angel, Beast and Marvel Girl (Jean Grey), calling them the X-Men because they possess an "extra" power which normal humans lack. The X-Men became a team that protects a world that hates and fears them. The team first fought archenemy Magneto, the former friend of Professor X, who believed that mutants should dominate humanity. Magneto would form his Brotherhood of Mutants to clash with the X-Men several times. Several new mutants joined the X-Men, including Cyclops's brother Havok. The title lagged in sales and Marvel comics stopped producing new stories with #66, instead reprinting stories from older comics from issues #67 - 93. In 1975, Giant-Size X-Men #1 was published with writer Len Wein and artist Dave Cockrum introducing a new team of international members including Storm (Kenya), Wolverine (Canada), Colossus (Russia), Nightcrawler (Germany) and Banshee (Ireland), among others.
The franchise became so popular that secondary titles featuring other mutants were published. In the 1980s, secondary titles included the student team book New Mutants; X-Factor, featuring the original X-Men of Cyclops, Jean Grey, Iceman, Angel and Beast; and the British superhero team book Excalibur. Prominent X-villains such as Apocalypse and Mr. Sinister debuted in this era.
X-Force replaced New Mutants, with the former student team becoming a militaristic outfit. A few years later, Generation X was published as the student team book. The 90s became a period known for wide crossover arcs with the various secondary titles. For more information on the various crossovers, check out Crossovers.
The 2000s is marked by a number of reorganization of the X-franchise. Chris Claremont returned to write both X-Men titles in 2000 but was removed from both in 2001. In this relaunch, writer Grant Morrison was brought in to helm the X-Men (vol. 2) title, re-titled New X-Men. Among the things he did was to make former Hellfire Club member Emma Frost an X-Man and opened the Xavier Institute to many mutant students. He also introduced the X-Corporations to provide support for the mutant population worldwide. Uncanny X-Men was written by Joe Casey and later Chuck Austen. In the course of Casey's run, he introduced the X-Corp, a paramilitary unit formed by the former X-Man Banshee to police the mutant population. The unit was infiltrated by Mystique and her Brotherhood and eventually disbanded. Chris Claremont was given a third X-Men title called X-Treme X-Men. Secondary titles such as Generation X, X-Force and X-Factor were all eventually cancelled. New Mutants (vol. 2) was published to feature the students. When Grant Morrison departed the New X-Men title in 2004, there was an reorganization of the titles known as ReLoad.
In ReLoad, X-Treme X-Men was cancelled and replaced by Astonishing X-Men written by Joss Whedon, New X-Men was renamed X-Men (vol. 2) again and New Mutants (vol. 2) was replaced by New X-Men: Academy X, which was renamed New X-Men with issue #20. New writers were brought in to revitalize the franchise in 2006.
Yet another reorganization happened in 2010 following the Second Coming crossover. Generation Hope was published as a new title featuring the next generation of mutants. A fourth X-Men title X-Men (vol. 3) was also published. X-Force vol. 3 was relaunched as Uncanny X-Force.
From June 2011, the X-titles carry the MMXI (Year of the X-Men) tag, with new writers in some of the titles and new directions under the same writers in other titles.
A mini-series titled Prelude to Schism was published, leading up to the Schism event that saw the X-Men split between following Cyclops and Wolverine. Uncanny X-Men was cancelled with #544 and replaced with a brand new Uncanny X-Men #1 in November following Cyclops's team. A new X-Men title Wolverine and the X-Men was published in October.
A difference of ideas between Cyclops and Wolverine caused both to go their separate ways. Cyclops' X-Men continue to operate on their island home of Utopia off the coast of San Francisco. They are concerned with protecting mutant-kind and the world, while present an intimidating front to those who would threaten mutants. Wolverine's X-Men are concerned with setting up a school for young mutants and protecting them. This event is known as ReGenesis.
Uncanny X-Men: Flagship X-Men title featuring Cyclops' Extinction Team.
X-Men vol. 3: Features Cyclops' X-Men interacting with the rest of the Marvel universe.
New Mutants: Responsible for tying up the X-Men's loose ends.
Generation Hope: Features the Five Lights, search-and-rescue team for new mutants.
Xtreme X-Men: A team of X-Men from different alternate realities.
Wolverine and the X-Men: Flagship X-Men title featuring Wolverine's side.
X-Men Legacy: Features Rogue and a cast of X-Men on Wolverine's side.
Astonishing X-Men: A team of X-Men serving as heroes.
Uncanny X-Force: Features the hit-squad led by Wolverine.
X-Factor: Mutant investigation team led by Jamie Madrox, the Multiple Man
Wolverine: Solo title featuring Wolverine
In 2012, in the event Avengers vs X-Men, the arrival of the Phoenix Force triggered a war between the Avengers and the X-Men with the former believing that the Phoenix is a destructive force that will lay waste to the planet and the latter believing that the Phoenix will reignite the dying mutant race. The war came to a head on the moon when the Phoenix was divided between five mutants - Cyclops, Emma Frost, Namor, Colossus and Magik. The Phoenix Five went about changing the world for the better. The Avengers continue to attempt to neutralize the cosmic force but was declared outlaws by the X-Men and hunted down. Namor, Colossus and Magik lost their powers during attacks on the Avengers. In the final battle, Cyclops absorbed Emma Frost's portion of the Force fighting the Avengers. When Professor X attempted to stop him, Cyclops killed him. Cyclops was eventually defeated by the combined efforts of Hope Summers and Scarlet Witch. The Phoenix Force was splintered around Earth, reigniting the mutant population. Cyclops and Emma Frost were captured while the rest of their teammates fled. Cyclops' students joined Wolverine's Jean Grey School and Utopia is shut down.
After the Avengers vs X-Men event, there is a relaunch across Marvel with several titles ending and others relaunching. Under this Marvel Now relaunch, titles are either cancelled, relaunched or newly released.
In 2013, the X-Men were involved in the Battle of the Atom crossover.
History of the X-Men: History of the X-Men
List of all X-Men thus far: X-Men Roster
List of X-Men teams in images: Rosters
List of X-teams: Rosters
List of Villains: Villains
List of Crossovers and Events: Crossovers/Events
List of X-Men collection stories in chronological order: TPB Reading Order
History of Xavier Institute and the Student Body: Xavier Institute