Although rare diseases have captured public attention in recent decades, the lived experiences of people affected by these conditions remain on the periphery of medical anthropological inquiry. Focusing on Poland, Finland, and Sweden, and foregrounding notions of “rare” or “chronic” disease as an embedded category, this book critically analyzes entanglements between people and families with rare diseases and care practices that involve local healthcare policies, practitioners, and treatment modalities. Drawing on locally grounded case studies, Entanglements of Rare Diseases in the Baltic Sea Region constitutes a unique and important contribution to both global medicine and social science scholarship.