In 1997 DC launched a new line of giants designed to provide background information about their characters. The new line, dubbed "Secret Files", differed from its predecessor Who's Who in that stories were included in addition to the character profile pages. Most issues contained a longer lead story and a few shorter one or two page features. Some issues focused on particular characters or groups, while other issues were devoted to events and storylines.

The first issue of Secret Files featured the JLA which had recently relaunched under the guidance of Grant Morrison. Two editions were released with one including trading cards and better paper stock. This was the only Secret Files issue to have a deluxe version. After its debut, Secret Files was released on a more or less monthly basis until the Fall of 2000. From that point the frequency of publication declined almost annually. The last Secret Files issue to be released was in early 2010 featuring the Flash.