In a lively investigation into the boundaries between popular culture and early-modern science, Sara Schechner presents a case study that challenges the view that rationalism was at odds with popular belief in the development of scientific theories. Schechner Genuth delineates the evolution of people's understanding of comets, showing that until the seventeenth century, all members of society dreaded comets as heaven-sent portents of plague, flood, civil disorder, and other calamities. Although these beliefs became spurned as "vulgar superstitions" by the elite before the end of the...