From France to Brazil, Hungary to India, the Netherlands to the United States, the rise of authoritarian movements has reshaped global politics. At their heart lies the myth of the so-called 'great replacement theory', which insists that peoples of colour, migrants and minorities are being deliberately empowered to displace white majorities. In Chain of Ideas, Ibram X. Kendi traces how this conspiracy theory, once the preserve of the right-wing fringe, has mutated into a global ideology embraced by leaders as varied as Marine Le Pen, Viktor Orbán, Narendra Modi, Jair Bolsonaro, Nigel Farage, Benjamin Netanyahu and Donald Trump. From Anders Breivik's massacre in Oslo to the chants of the Charlottesville marchers, from Brexit slogans to the Christchurch shooting, Kendi shows how these ideas have crossed borders, inspired terror and re-shaped parties of government. This is not a book about extremists on the margins. It is a penetrating history of how reactionary ideas have been repackaged as common sense, and how they now shape governments across the globe today. Kendi demonstrates how mainstream politicians and billionaires - from Elon Musk to Giorgia Meloni, from Geert Wilders to Pierre Poilievre - have drawn on and spread this dogma through media platforms, cultural battles and populist anger and amplified them in moments of economic crisis, pandemic and migration. He exposes the deep historical lineages of this ideology, with its roots in slavery, segregation, colonialism and fascism, that continue to shadow the present and how older prejudices have been dressed in new language for a digital age. Urgent, authoritative and unflinching, Chain of Ideas is a chilling but essential global history of our authoritarian age and a powerful call to defend democracy before it is too late.