Fellow Record Test My work uncovers a significant, but overlooked feature of the industrial revolution: an industrial slave economy that linked diverse areas of the Atlantic World. Strung together by railroads, steamships, canals, and telegraphs, slave-exploiting industries from Havana, Matanzas and Rio de Janeiro to Richmond, Baltimore and Durham constituted a system of transnational industrial slavery that has not been covered in the scholarship on slavery in the Atlantic world. I analyze this element of the mid-nineteenth-century world economy by looking at the commercial interactions among slave-exploiting industrial concerns such as iron works, flour and sugar mills and tobacco manufacturers in Cuba, the United States and Brazil. In spite of the fact that their respective national historiographies have discussed them in isolation from one another, these slave-exploiting industries were shipping millions of dollars’ worth of milled flour, manufactured tobacco products, steam engines, refined sugar, railroad hardware and other manufactures within a transnational network of slave-centered economies. Thus a seemingly anomalous picture comes into focus: some of the more profitable industrial enterprises of the nineteenth century, tied to the advanced technological apparatus of steam-powered locomotives and ships, exemplify the modernizing mid-nineteenth century global economy. This growth, however, was grounded in slave labor. While examining a number of different, interlocking industries, my study focuses particular attention on the counterpoint between the important slave-operated sectors of the U.S. iron industry and the Cuban sugar/railroad complex. This element of the wider system of transnational industrial slavery constituted a crucial aspect of Cuba’s changing position between empires, and encourages us to rethink the place of slavery in the mid-nineteenth century industrial boom in the Atlantic world.