In the expansive corpus of critical writing that has accrued around the works of W. G. Sebald, two factors are almost universally agreed upon. The first concerns the heterogeneous nature of his four novels, insofar as they combine elements of biography, memoir, travelogue, archival research, collage, photographic essay and fiction. The second near-unanimous claim is that the Holocaust is the absent determinant that impels all his writing, and that accounts to some extent for the mixture of styles and genres (as a way of overcoming the prohibition on direct confrontation of that unrepresentable event). In this essay, I contest both claims. Focusing mainly on The Rings of Saturn (1995) and Austerlitz (2001), I stress the constants that bind Sebald's fiction together, starting with the motif of gaseous matter, particularly smoke, and then working through to the more historically overdetermined incidences of fire. In doing so, I suggest that the centre of gravity has shifted, and that Sebald's historical poetics has acquired a new historical grounding. Finally, I propose a pre-Socratic precedent for this summa theoretica of Sebald's work, widening the critical field as it threatens to devolve into a fixed roster of themes, influences and historical precedents.