Published as the companion piece to Observations upon Experimental Philosophy (1666), Margaret Cavendish’s fantastical travelogue Blazing World (1666) dramatizes and interrogates many of the ideas that the author put forth in her philosophical writing. Cavendish might have chosen the travel genre as the companion piece to her treatise on natural philosophy for a variety of reasons. One primary motivation, this essay argues, is that travel has intriguing thematic and epistemological links to her organic-materialist theory of the universe. Indeed, travel is built into Cavendish’s ontology: motion is a precondition for being and knowing. With this in mind, Blazing World’s engagement with the voyage genre becomes particularly important. At the same time, Blazing World is more resolutely experimental than Observations in that it investigates the possible loopholes and ambiguities of her materialist theory of nature. Cavendish is fascinated by how material bodies compose ideas, and how ideas take material form, and it is some of her recurring questions about the materiality and mobility of thought that she explores in Blazing World.