The book departs from the traditional view of Mediterranean history with its emphasis on the influences of physical geography. Instead it regards physical context as a staging ground for decisive action with, at center stage, human catalysts at all levels of society—from great kings and emperors to the sailors of medieval Amalfi to the Sephardic Jews who were expelled from Spain in 1492. The authors describe how these groups interacted with one another across the sea, enjoying commercial and political ties as well as sharing ideas and religious beliefs.