Once only a vague metaphor to describe the relationship between different social groups, the term “social distance” has acquired a precise meaning during the Covid-19 pandemic. It is the mandatory minimum distance for face-to-face contact between persons, and can vary slightly depending on the jurisdiction. Rather than asserting a diagnosis of our contemporary global emergency, this issue offers perspectives from architectural history and theory. From the great plague of Venice to cholera in the industrialising city, and from the human placenta to the 1960s bubble or the office of today, here a broad range of reflections on contagion, disease, and health can be found.