Schechner weaves together many strands of thought: views of comets as signs and causes of social and physical changes; vigilance toward monsters and prodigies as indicators of God's will; Christian eschatology; scientific interpretations of Scripture; astrological prognostication and political propaganda; and celestial mechanics and astrophysics. This exploration of the interplay between high and low beliefs about nature leads to the conclusion that popular and long-held views of comets as divine signs were not overturned by astronomical discoveries. Indeed, they became part of the foundation on which modern cosmology was built.