The introduction situates the work of the book within critical feminist theories of monogamy and feminist conversations about science and its proper objects. It explains how the book’s objects of inquiry, primary sources, and critical methodologies contribute to a naturecultural approach to monogamy, one that accounts for its histories, contexts of intelligibility, and embodied realities. The book’s central questions are outlined: What is the relationship between how we imagine social belonging and how we understand human nature? What modes of conceptualization might enable new forms of being and belonging we cannot yet imagine? What conceptions of materiality might reflect the breadth of feminist and other contributions to knowing bodies? The introduction insists that the politics of science and the possibilities of biology are not separate sets of concerns but questions we must work to integrate.