ABSTRACTProcesses for the identification of criminal suspects tell us a great deal about wider cultural assumptions and social prejudices regarding somatic difference; its causes, relative degree, and consequence. If early modern Europeans had something approaching a forensic science, it was astrology, which has recently garnered renewed attention from historians of ideas. Rather than assume astrology's seventeenth-century decline in the face of revolutionary natural philosophy, what follows suggests that English astrology remained significant for mundane bodily discrimination, in the context of both a more deliberate, gradual reform and the tenacity of centuries-old humoral physiology. More importantly, scrutiny of astrological practice, and the logic underpinning its lasting currency, can reveal much about the significance of bodily contrasts and the meanings ascribed to them by Tudor-Stuart folk.