Books which feature some element of color-coding different groups of people by their clothing, usually in a hierarchy but also in some cases by magical or elemental affinity, nation, or political affiliation. Science fiction, fantasy, graphic novel, and non-fiction examples all accepted.

If you add a book where the color-coded element is not obvious from the title or blurb, please add a comment explaining what the color-coding element in the book is to help people searching for books find what they're looking for!

LONG SERIES RULES: If the color-coding is specific to ONE and ONLY ONE book in a series, add the book in which the color-coding appears. Please add a note explaining this in the comments.

For all other cases, ONLY add the FIRST book in the series or a Goodreads listing with all of the series in one link. I reserve the right to remove any series books which appear to violate this rule.