Between June 12 and June 23, 1840, more than 500 abolitionists met at Exeter Hall and debated the state of slavery throughout the world. More than 1,000 spectators attended the morning and evening panels daily as this international delegation discussed their ideas, views, and plans for how to bring the different forms and systems of slavery to an end. While this international convention included abolitionists from Spain, France, Switzerland, the British West Indies, Haiti, Canada, South Africa, British Guiana, most of the attendees (roughly 400) came from Great Britain and the United States. By uniting minds and hearts, this antislavery conference produced one of the nineteenth century’s most comprehensive bodies of scholarship on slavery and abolition The Convention of 1840 represented an impressive and unique achievement for this time. As later generations of antislavery and human rights activists attended similar international conferences and meetings, their scholarly activism benefited from Special Rapporteurs, transnational non-profit and interstate organizations that arranged these gatherings, and academic scholarship on slavery recognized by elite institutions. The international delegation of abolitionists at the Convention 1840, however, started their knowledge production and exchanges without these advantages. This is a dissertation about how knowledge production and information politics in the antislavery movement got started, as well as the additional obstacles that arose in this transnational crusade. In five chapters, this dissertation explores how Anglo-American abolitionists investigated systems of slavery outside of their national antislavery movements and how this knowledge shaped their activism and relationships with other reform groups. I achieve three primary objectives. First, I show how antislavery knowledge shaped the development of the transatlantic antislavery movement. Second, I show that antislavery organizations and abolitionists did not consider all forms of slavery the same. By following the scholarship that abolitionists produced about different systems of slavery, this study reveals that antislavery societies and abolitionists had an informal hierarchy that characterized specific slave systems as worse and more in need of eradication than others, which in part, gives coherence to the uneven and seemingly erratic development of the transatlantic antislavery movement. Finally, this dissertation argues that information and knowledge production lay at the heart of abolitionism. The creation and circulation of knowledge informed Anglo-American antislavery societies of where they needed to direct their attention, resources, and activism.