Xavier Plassat is a friar of the Dominican order, a Frenchman who has worked for decades in the Brazilian Amazon and is renowned for his fight against slavery as it exists in our time. Modern slavery differs from classic chattel slavery, in which people are held as private property, but to the extent that it treats people as tools to be used and discarded, it is nearly as brutal and degrading. Currently it affects perhaps 20 million people, and probably many more. Relatively few are women tricked into prostitution; a greater number, men and women alike, are manual laborers in forests, fields, and factories, or at sea. It is possible to get caught up in the technicalities of definition. Those who rely on slaves for labor want as narrow a definition of “slavery” as possible. Brazil officially recognizes a broad definition, and for that reason it has made more progress against slavery than similar countries have. Still, in the Amazon alone tens of thousands of workers are enslaved at any given time.