This is our top-level category, or looking at it another way, it is the root category.
Ideally, every other category should be a subcategory of at least one other, and every article should be in at least one category; many will fit well into two (e.g. location and subject-matter).
The Category:Control is the central category for everything in-universe, everything derived from fiction, from within the Blake's 7 universe goes within this category or its sub-categories.
Category:Real world is for everything concerning the real world, the stories, writers, directors, producers, designers and everything else that helped create and define Blake's 7.
Category:Star One for everything concerning the actual running of the wiki, the templates that hold pages together, the policies that define the wiki, the maintenance category that tells us what is flooding and what isn't.
Nothing aside from the main page should be within this category, everything should be categorised into one of these three:
A full list of existing categories can be found at Special:Categories.
To add a new category to a page, just add
[[Category:Categoryname]] to the end of the article or existing category page.