Technically speaking, slavery was not legal in the English-speaking world before the mid-seventeenth century. But long before race-based slavery was entrenched in law and practice, English men and women were well aware of the various forms of human bondage practiced in other nations and, in less systematic ways, their own country. They understood the legal and philosophic rationale of slavery in different cultural contexts and, for good reason, worried about the possibility of their own enslavement by foreign Catholic or Muslim powers. While opinions about the benefits and ethics of the...