In the introduction, the book’s central framing of using ‘diversity formations’ as an analytical tool for understanding the politics of difference in early modern to modern European empires is laid out. Four key features of this conception are introduced: (1) the historically and politically contingent constitution of diversity formations, (2) the interaction of multiple groups and agents in the exclusions, modes of belonging, and hierarchies that shape diversity in empires, (3) the resilience of diversity formations across periods and settings, and (4) the intersectional and interactive nature of modes of conceiving difference. Next, the goal of this diversity-based approach – to move beyond prevalent analytical dichotomies toward a more dynamic understanding of empire – is explained, before laying out the book’s structure.