Race has been one of the most consequential ideas in modern history, and the aims of this book are to better understand its intellectual genesis and proliferation. The introduction sets out the key themes of the volume and serves as a prelude to the geographical and temporal spread of the following chapters. Although the idea of ‘race’ emerged in European vernaculars in the late middle ages, we trace lines of continuity in its understanding and usage from the eighteenth century to the present. By juxtaposing discrete case studies of how race was conceptualised in different places over this period we hope to shed light on how the intellectual category of race that we have inherited was constructed, while showing connections between ideas and experience.