Short answers, pulled from the story.
Historians consider Famous Funnies: A Carnival of Comics, published in 1933, the first true American comic book. Eastern Color then published Famous Funnies #1 with a July 1934 cover date, printing 200,000 copies and selling 90 percent of the run.
Superman debuted as the cover feature of Action Comics #1, dated June 1938. The character was created by Jerry Siegel and Joe Shuster, who had already published other work in New Fun comics as early as October 1935.
The Comics Code Authority was a self-censoring body founded in 1954 by a group of publishers led by National and Archie Comics. It was created in response to Senate hearings on juvenile delinquency and public pressure following psychiatrist Fredric Wertham's book Seduction of the Innocent, which blamed crime and horror comics for negative effects on youth.
Circulation peaked in 1952, when 3,161 individual issues were published with a combined total circulation of approximately one billion copies. After 1952, the number of releases dropped every year through the rest of the decade.
Stan Lee and Jack Kirby created the Fantastic Four in 1961 at the direction of publisher Martin Goodman, introducing a naturalistic superhero style featuring characters with human failings and personal conflicts. From 1957 to 1968 Marvel was restricted by its distributor to publishing only eight titles a month, which forced concentration of talent on a small number of books and drove up quality and sales.
Some American comic books have sold for more than one million dollars. Collectors use plastic sleeves and cardboard backing boards to preserve valuable issues, and comic specialty stores cater specifically to this collector market.