Mintz asks, seriously rather than rhetorically, whether enslaved people on Caribbean sugar estates can usefully be called proletarians, and refuses a quick answer in either direction. His starting point is Marx's distinction between formal freedom and the sale of labour-power, which makes clear that a free labourer is not automatically a member of the proletariat.

Slavery, he insists, varied too much by colony, crop, period and demography for a single characterisation to hold; his own discussion narrows to the sugar estates of the Antilles across four centuries. What the enslaved shared with wage workers was subordination to a capitalist world market; what they lacked was any freedom to sell their labour at all.

Following Wallerstein, he suggests the two categories only make sense in relation to the whole system that produced both, and closes less with a verdict than with a warning that the terms themselves, and the adjectives free and unfree, are abstractions in need of repair.