The Great Replacement is a 74-page manifesto authored by Brenton Tarrant, the perpetrator of the 2019 Christchurch mosque shootings. The document outlines white supremacist ideologies and promotes anti-immigrant conspiracy theories centered on the 'Great Replacement' concept—originally coined by French writer Renaud Camus—which claims that white populations are being systematically replaced by non-white immigrants through mass migration and declining birth rates. It includes justifications for the Christchurch attacks, references to other far-right figures and events, and calls for violence against perceived threats to white identity. The manifesto has been widely condemned as hate speech and has influenced subsequent extremist attacks, contributing to the spread of replacement theory in online radicalization networks.