The Renaissance philosopher Giordano Bruno was a notable supporter of the new science that arose during his lifetime; his role in its development has been debated ever since the early seventeenth century. Hilary Gatti here reevaluates Bruno's contribution to the scientific revolution, in the process challenging the view that now dominates Bruno criticism among English-language scholars. This argument, associated with the work of Frances Yates, holds that early modern science was impregnated with and shaped by Hermetic and occult traditions, and has led scholars to view Bruno primarily as a magus. Gatti reinstates Bruno as a scientific thinker and occasional investigator of considerable significance and power whose work participates in the excitement aroused by the new science and its methods at the end of the sixteenth century. Her original research emphasizes the importance of Bruno's links to the magnetic philosophers, from Ficino to Gilbert; Bruno's reading and extension of Copernicus's work on the motions of the earth; the importance of Bruno's mathematics; and his work on the art of memory seen as a picture logic, which she examines in the light of the crises of visualization in present-day science. She concludes by emphasizing Bruno's ethics of scientific discovery.