The role and status of writing in scientific practice have become central concerns in the history and philosophy of science. Investigations into the rhetoric of scientific texts, the ‘language games’ of calculation, experimentation and proof, and the uses of textbooks, reports and specialized journals in the formation of scientific communities have all brought a growing awareness of what the American author Edgar Allan Poe (1809–49) heralded as ‘The Power of Words’. In discussing several works of this author, who perhaps more than any of his ‘literary’ contemporaries grappled with the growing dominance of science and technology in his time, this paper shows the potential ambiguity and polyvalence of the rhetoric of science. Poe's writings exploit this increasingly powerful language in a variety of ways: through logical proofs, satires, hoaxes, and the analysis of mysteries, codes and poetry, notably his own. Poe's unorthodox use of scientific rhetoric highlights the importance of historically specific modes of discourse for the consolidation of truth.