The first two cantos of Lord Byron's Don Juan were published in 1819 and caused an extraordinary outcry in the press and in private. In Newcastle the Literary and Philosophical Society decided, after a lengthy series of debates, publications and counter-publications, that the poem was unfit for a place in its library. Drawing on papers held at the Lit & Phil and publications in the local press I reconstruct the debate. It is important both for what it tells us about cultural institutions like the Lit & Phil and for what it suggests about the unusually unsettling effect Byron's poem had. Literary and Philosophical Societies were an important part of the long eighteenth-century cultures of conversation explored recently by scholars. The debate about Byron's poem suggests the tensions in that culture were, by the Regency, coming to breaking point. But the peculiar character of the reaction, the oddly perplexed outrage Don Juan prompted, suggests the deeper ways in which the poem destabilized the nature of reading in the Romantic period.