The Fantastic Four consists of four heroes, Reed Richards, Benjamin Grimm, Susan Storm (later Richards), and Johnny Storm. When an experimental rocket flight planned by Richards and Grimm is cancelled, the four sneak onto the launch pad and take off in the rocket themselves. Once they leave the Earth's atmosphere, the rocket is subjected to unknown cosmic radiation, against which the craft is unshielded. The four crash land back on Earth, but not before the radiation takes its toll. .
Reed Richards gained the ability to bend and stretch his body into any number of incredible shapes. He took the name Mr. Fantastic. Ben Grimm's skin changed into an orange, rocky crust, and his strength increased tremendously. He now called himself The Thing. Johnny Storm's body burst into flame, but was not consumed. In fact, as the Human Torch, he could now fly and control fire. After the crash, the other three couldn't find Susan Storm. They had to track her down by the sound of her voice, since she had become invisible. She learned to control this power, and the Invisible Woman, as she's now known, can also create invisible force fields. The four survivors vowed to use their new abilities for the good of humanity, and the Fantastic Four was born. .
The Fantastic Four was an unusual superhero group right from the beginning. They wore no costumes, and made no attempt to keep their identities secret. In fact, they argued among themselves all the time. The writer and co-creator of the book, Stanley Lieber, who now used the pen name Stan Lee, wrote the four as more of a family than a team, and this family fought each other as hard as any real one. The FF got uniforms by their fourth issue, along with a high-tech headquarters and gadgets by the ton. In another dose of reality though, Stan Lee gave the FF the money problems that all have, even to the point of having them lose the headquarters they thought they owned.