The product is a vintage comic book titled "JUSTICE LEAGUE OF AMERICA #21 AUG 1963" featuring the first appearance of the Crisis on Two Earths storyline that would become a continuous yearly storyline.Written by Gardner Fox and illustrated by Mike Sekowsky, this issue falls within the Silver Age era of US Comics. Comic is in very solid condition except for a scratch in the lower left corner that does go into the comic,but not on the story pages.Published by DC Comics, this collectible is a valuable addition to any comic book collector's arsenal as it showcases a pivotal moment in the history of the Justice League of America superhero team.