In a series of articles published in Tait's Magazine in 1834, Thomas DeQuincey catalogued four potential instances of plagiarism in the work of his friend and literary competitor Samuel Taylor Coleridge. DeQuincey's charges and the controversy they ignited have shaped readers' responses to the work of such writers as Coleridge, Lord Byron, William Wordsworth, and John Clare ever since. But what did plagiarism mean some two hundred years...