The Fantastic Four...
...the super-strong monster Thing (Benjamin J. Grimm), leader and elastic in mind and body Mr. Fantastic (Reed Richards), the fiery Human Torch (Johnny Storm) and the hard to see Invisible Girl (Sue Storm, later Sue Richards). Four friends who premiered in Fantastic Four #1 (November, 1961 by Stan Lee and Jack Kirby).
At one point, this was considered to be the start of the Marvel Universe...
...
.the original X-Men were created "in the sensational Fantastic Four style" and
the Avengers formed when Rick Jones' call for help with the Hulk to the FF was redirected to Iron Man, Ant-Man, Wasp and Thor!
The Fantastic Four had met the Hulk and Ant-Man before the Avengers even formed, and when Spider-Man was looking for money, he went to try to join the Fantastic Four!
Friends of the Fantastic Four
The Inhumans slowly worked their way into the life of the Fantastic Four...starting with
Medusa (as a member of the Frightful Four, along with the Wizard, Paste-Pot Pete and the Sandman, in
Fantastic Four #36 in March, 1965 by
Stan Lee and
Jack Kirby), then followed by Gorgon in
Fantastic Four #44 (November, 1965, also by
Stan and Jack), and the whole royal family of Inhumans (including leader Black Bolt, Karnak, Triton and Crystal) in
Fantastic Four #45 (December, 1965 also by
Lee and
Kirby).
The Inhumans were a race of humans modified by exposure to the Terrigen Mists to have powers and abilities far beyond those of normal humans, and they lived apart from humanity in their city of Attilan. The Inhumans saga slowly evolved over issues of the Fantastic Four, with the lovely Crystal being the object of affection of the Human Torch...(and Crystal becoming a member of the Fantastic Four for a time, when Sue had to take maternity leave after the birth of her and Reed's son, Franklin...starting in
Fantastic Four #81 of December, 1968).
But, the Inhumans couldn't be contained to one book...having their history explored in
Thor and elsewhere, and graduating to a few series of their own, like a 10 issue run in
Amazing Adventures #1 to
#10 from August, 1970 to January, 1972, to their first self-titled series with the
Inhumans #1 to
#12 from October, 1975, to August, 1977 and oh so many more!
The Inhumans worked with Black Panther as well, another friend of the FF, who premiered in
Fantastic Four #52 (July, 1966 by Lee and Kirby again). T'Challa was a prince of the African nation of Wakanda, the home of the unique metal of vibranium...and he wished to prove his meddle against the Fantastic Four, and did! Black Panther became a quick ally of the team when
Klaw killed T'Challa's father, T'Chaka (
Fantastic Four #53, August, 1966).
Black Panther worked with the FF against a few foes quickly, ending with Psycho Man in
Fantastic Four Annual #5 (November, 1967)...before moving on, meeting Captain America and soon
joining the Avengers!
Black Panther worked with the Avengers for a time, but graduated to his own series as well, first in
Jungle Action from issues
#5 to
#24 (July, 1973 to November, 1976), and then in the first of his own series,
Black Panther, starting with issue
#1 in January, 1977, lasting until issue
#15, in May, 1979...
...oddly, with both those series ending elsewhere...and the Black Panther getting more series as well...
Foes of the Fantastic Four
An early foe of the Fantastic Four was the Sub-Mariner...and Namor was a foe of the whole human race! Starting with
Fantastic Four #4 (May, 1962), when Johnny Storm found a derelict in a homeless shelter...and cleaned him up to realize he was Namor, the Sub-Mariner! Namor thought he lost his city of Atlantis, and vowed to take revenge on the human race (though being a threat to the family of the Fantastic Four as well, as he had intentions toward the Invisible Girl as well...much to the annoyance of her beau, Mr. Fantastic!). Namor used his aquatic powers in a few early battles with the FF, culminating in
Fantastic Four Annual #1 (September, 1963), when Namor found out that his people were still alive!
But, that wasn't the end of Namor's tale...or the trouble he would cause the Fantastic Four, in more ways than one. While battling the FF (and soon after, the
Avengers, with the Hulk, no less), the Sub-Mariner also freed Captain America from his prison in ice (allowing
Cap to join the Avengers!).
With Cap and Namor now active, it was realized that the Fantastic Four weren't the start of the Marvel Universe (and there was a whole history of Marvel characters from before, with Timely Comics, where Sub-Mariner and Captain America had comics, along with a different android Human Torch!).
All this didn't stop Namor from going on, taking the shared spot with the Hulk away from Giant-Man in
Tales to Astonish (from issues
#70, August, 1965 to
#101, March, 1968, though Namor's last cover was
Tales To Astonish #100 of February, 1968) and getting the first of his post meeting with the Fantastic Four starting with
Sub-Mariner #1 in May, 1968, lasting until
Sub-Mariner #72 September, 1974...
...with Namor's creator,
Bill Everett coming back to do work on more than a few issues of
Tales to Astonish (
#85-91,
#94-96) and
Sub-Mariner (
#50-55, and parts of
#58-60), ending his association with
Sub-Mariner #61 (May, 1973), which he died before completing more than 3 pages (with the rest of issue being finished by writer
Steve Gerber, artist
Win Mortiner and inker
Jim Mooney).
But, Namor wasn't without a title for long, ending up in one with fellow Fantastic Four foe, Dr. Doom (that of
Super-Villain Team-Up).
But, Dr. Doom existed before that series started...facing off against the Fantastic Four in
Fantastic Four #5 (July, 1962, by
Stan Lee and
Jack Kirby), and had been a thorn in the lives of the Fantastic Four even before they went on their voyage to space and received their powers.
Victor von Doom was a college classmate of Reed Richards and Ben Grimm, who was annoyed by Reed's being a better scientist than Doom. After an accident in the lab where he was working (which Reed tried to warn him about), Doom left the university, to head to Tibet, making his armor and then going to home to Latveria to take that country over (all from
Fantastic Four Annual #2, September, 1964).
Dr. Doom also made the rounds, working with other villains like the Sub-Mariner (in
Fantastic Four #6 in September, 1962), and even facing other members of the Marvel Universe, like Spider-Man (in
Amazing Spider-Man #5 in October, 1963) and the Avengers (starting with
Avengers #24-25, January-February, 1966 or earlier, as later reports came in)!
Dr. Doom's first solo tale came with
Marvel Super-Heroes #20 (May, 1969), with Doom having to take on fellow Fantastic Four foe, El Diablo, who had tried to influence Doom by taking Valeria (the love of Doom's life)...
...but you can read more on this
here, with the title becoming mostly reprints after his appearance, Dr. Doom DID defeat the Marvel super-heroes!
Still, Dr. Doom continued on, getting his own series (with Ka-Zar), which lasted for 8 issues in
Astonishing Tales (
#1 to
#8, August, 1970 to October, 1971), where Doom faced Prince Rudolfo, the Doomsman, the Faceless One (
Astonishing Tales #1 to
#3), Red Skull (
Astonishing Tales #4 and
#5), Black Panther (
Astonishing Tales #6 and
#7, trying to get at Wakanda's vibranium), and even "Satan" in
Astonishing Tales #8 (where Doom tries to save the soul of his mother, Cynthia)!
Doom tried another series as well, with Namor, the Sub-Mariner, starting with 2 issues of
Giant-Size Super-Villain Team-Up (in March and June, 1975), and then continuing for 14 new issues with
Super-Villain Team-Up starting in August, 1975 (though Namor took off with
Super-Villain Team-Up #13, and X-Men foe
Magneto and odd super-group
the Champions were the guest of
Super-Villain Team-Up #14 in October, 1977, and a reprint of the two
Astonishing Tales battles with the Red Skull filled
Super-Villain Team-Up #15 in November, 1978).
All this villainy, where can heroes turn?
Family
Everyone is a part of the Fantastic Four family, from Inhumans like Crystal and Medusa, to Heroes for Hire like Luke Cage, She-Hulk and Ant-Man...that was the charm of the Fantastic Four....it was a party, and everyone was invited!
The family was the core of what made the Fantastic Four such an important part of the readers lives...and, by extension, made the whole of the Marvel Universe part of our family as well.
....with Spider-Man as Luke Skywalker, Moondragon as Princess Leia, Marvel Boy as Han Solo, Paul the Gorilla from Electric Company as Chewbacca, Sam the Sesame Street Robot as R2-D2 and C-3PO, Dr. Doom as Darth Vader and his Doombots as Stormtroopers, as Dr. Doom used his new space station, Star Jaws, to try to eat the Earth!
It was a simpler time. 
