Martin Heidegger begins his lecture '⋯ Poetically Man Dwells ⋯ ' by denying poetry is a marginal practice whose imaginings are 'mere fancies and illusions'. '[T]he poetic', he states, is not 'merely an ornament and bonus added on to dwelling'. On the contrary, Heidegger boldly claims that poetry is the source of all human dwelling on earth: '[⋯ ] poetry first causes dwelling to be dwelling. Poetry is what really lets us dwell.' The connective tissue of Heidegger's argument in '⋯ Poetically Man Dwells ⋯ ' is the concept of 'measure'. In the English translation of the lecture, permutations of the term 'measure' (Maβ/messen) appear a remarkable ninety-four times, not including dozens more uses of its synonyms: 'dimension', 'span', 'meter' and 'gauge'. What seems surprising, given that the set-up of the lecture revolves around poetry and measure, is that the commonest understanding of measure related to poetry - poetic measure itself - is not discussed thematically by Heidegger. Rather, Heidegger's incessant word play produces meanings that include 'measuring against' in the sense of comparing to a standard, 'measuring up' a space by 'stepping-out' (durchmessen), 'measuring out' in the sense of dividing-up or apportioning (das Zu-Gemessene), 'being measured' in the sense of having propriety, 'taking measures' (die Maβ-Nahme) in response to a situation, and 'measuring between' as a distance or span. These meanings are of course related to common poetic measure, and might even be claimed to be its ground. Copyright © Cambridge University Press 2014.