In addition to describing the places he sees and people he encounters, including translator Michael Hamburger, Sebald discusses various episodes of history and literature, including the introduction of silkworm cultivation to Europe, and the writings of Thomas Browne, which attach in some way to the larger text.

According to Patrick Lennon's "In the Weaver's Web" (and Mark McCulloh's Understanding W. G. Sebald), The Rings of Saturn merges the identities of the Sebaldian narrator with that of Michael Hamburger – Sebald and Hamburger both being German writers who moved to England and shared other important experiences.

Sebald flattens the temporal hierarchy of meaning, by giving equal significance to historical and modern events.

The title of the book may be associated with thematic content contained in the two passages – one appearing as part of the book's epigraph, the other in the fourth chapter, which mentions Saturn – hinting at both astronomical and mythological associations for Sebald's use of the word: The rings of Saturn consist of ice crystals and probably meteorite particles describing circular orbits around the planet's equator.

The shadow of the night is drawn like a black veil across the earth, and since almost all creatures, from one meridian to the next, lie down after the sun has set, so, he continues, one might, in following the setting sun, see on our globe nothing but prone bodies, row upon row, as if leveled by the scythe of Saturn – an endless graveyard for a humanity struck by falling sickness.