Book excerpt: British Captives from the Mediterranean to the Atlantic, 1563-1760 provides the first study of British captives in the North African Atlantic and Mediterranean, from the reign of Elizabeth I to George II. Based on extensive archival research in the United Kingdom, Nabil Matar furnishes the names of all captives while examining the problems that historians face in determining the numbers of early modern Britons in captivity. Matar also describes the roles which the monarchy, parliament, trading companies, and churches played (or did not play) in ransoming captives. He questions the emphasis on religious polarization in piracy and shows how much financial constraints, royal indifference, and corruption delayed the return of captives. As rivarly between Britain and France from 1688 on dominated the western Mediterranean and Atlantic, Matar concludes by showing how captives became the casus belli that justified European expansion.