The group debuted in The Fantastic Four #1 (1961). The Fantastic Four was the first superhero team created by writer-editor Stan Lee and artist/co-plotter Jack Kirby, and it was a roaring success with the release of the first issue.
The success was so huge that it influenced Stan Lee to jilt the idea of leaving the comic industry for good, and stay on.
Within the comic industry, there is a saying that the formation of the team was somewhat inspired by the success of another superheroes team under the publication of National Periodical Publications (later known as DC Comics) - the Justice League of America.
Affectionately known as the FF in short by fans, its team stories branch out massively and it will take countless gigabytes to finish accounting. Not to mention the affiliation of the group to other superheroes, sometimes seeing other friendlies substituting for members missing in action. There was even a time when the whole team got substituted by the eye-popping combo of Wolverine, Spiderman, Ghost Rider, and the Grey Hulk.
Funnily, this formation received quite a decent positive response from the readers and was brought back several times under different titles. It was to an extent being named as the New Fantastic Four.
In the latest recall of the group in 2012, we see some replacements in Venom, X-23, Red Hulk, and Ghost Rider.
Mister Fantastic (aka Reed Richards)
A scientific genius and the leader of the group, who can stretch his body into incredible lengths and shapes.
The Invisible Woman (aka Susan "Sue" Storm)
Eventually married Reed, who can render herself invisible and later project powerful force fields.
Human Torch (aka Johnny Storm)
Sue's younger brother, who can generate flames, surround himself with them and fly. Great to note that he is also one of the first few superhero friends Spiderman got acquinted to. He is also responsible for designing the latter's shortlived Spidermobile.
The Thing (aka Ben Grimm)
The grumpy but benevolent friend, a former college football star and Reed's college roommate as well as a good pilot, who possesses tremendous superhuman strength, durability, and endurance due to the nature of his stone-like flesh.