Keys of Knowledge was the title that Gold Key used for a series of features that were included with their various comic titles, including The Twilight Zone. The features were one-page sheets listing factual information on a range of topics, typically printed with six black and white panels for illustration. Topics included the history of nations, inventions, architecture, the cultures of foreign lands and animals, sometimes matched to the subjects addressed in the stories of the issue. The artists for the features varied, but included names like Mike Sekowsky and Joe Certa.