This document provides information about binary oppositions including: - A definition of binary opposition as a pair of related terms that are opposites in meaning, such as positive-negative. - The origins of binary opposition in Saussurean structuralist theory where units have meaning based on their relation to another term. - Examples of binaries in literature, religion, and society including male-female, hero-villain, heaven-hell, and obedience-disobedience. - How authors use binaries to explore differences between groups and the problems that can arise from rigid categorization, as shown in J.K. Rowling's Harry Potter series.