A rare copy of "Action Comics No. 1," the 1938 comic book that introduced Superman, has sold for a record 15 million in a private transaction. This sale surpasses the previous record of 9.12 million for "Superman No. 1." The comic, originally costing 10 cents, is considered the start of the superhero genre. This particular copy has a notable history, including being stolen from actor Nicolas Cage and later recovered. Approximately 100 copies of "Action Comics No. 1" are known to exist.