This presentation discusses prejudice and bias in controlled vocabularies and classification systems. It defines key terms like prejudice, bias, controlled vocabularies and classification. It provides examples of prejudice and bias in subject headings like those used in the Library of Congress Subject Headings. It also discusses how prejudice and bias can be built into systems through principles like literary warrant and through the language used. Finally, it suggests ways to address these issues by working locally to expand vocabularies and globally to re-examine assumptions in subject access.