"Berry studies the economic history of slavery in the United States, examining how a price was assigned to the bodies of enslaved people in America from before they were born until after they died.^[5] Berry proposes four types of value that an enslaved person could hold: their assessed value, as determined by others for the purposes of accounting and sale; their market value, which was a function of local demand; their soul value, derived from inherent spiritual self-worth and reinforced by familial and communal connections; and their ghost value, evaluated by body brokers who engaged in the sale of human cadavers" (Wikipedia)