By one estimate, between 350,000 and 500,000 colonists came to America as compulsory laborers. Some came as indentured servants, others as convicts. The transportation of servants into Maryland, in particular, reached its height in the middle of the 18th century, while convicts arrived there in ever-increasing numbers prior to the onset of the American Revolution. For the investors who underwrote the transportation of forced labor-brokers, ships'...