In 1500, literate Europeans lived in a bounded, geocentric universe. By 1800, the sun had replaced the earth at the centre of a limited planetary system situated in infinite space. These changes prompted early modern philosophers, scientists and writers to consider the possibility that the universe might contain a plurality of worlds. This course will explore the ways in which the “plurality” theme was developed in some of the earliest works of science fiction. We will consider this theme as it appears in stories of intergalactic voyages, utopian societies, and encounters with extraterrestrial beings, paying special attention to the ways in which early modern writers used these tales to speculate on philosophical, political, and scientific issues.