In the century after Emancipation, the long shadow of slavery left African Americans well short of the freedom promised to them. Sharecropping and debt peonage entrapped Black people in the South, and across the world, European colonialism had bred a new slavery that menaced the liberty of even more Africans. A core group of Black freedom movement leaders, including Ida B. Wells and W.E.B. Du Bois, followed their nineteenth century predecessors in insisting that the continuation of racial slavery anywhere put Black freedom on the line everywhere. They even predicted the consequences that ignited the recent nationwide Black Lives Matter movement - the rise of a prison industrial complex and the consequent erosion of African Americans' faith in the criminal justice system. The Freedom Movement's Lost Legacy is the first historical account of the Black freedom movement's response to modern slavery in the 20th century. Keith P. Griffler details how the mainstream antislavery movement became complicit in the enslavement of Black and brown people across the world through its sponsorship of racist international antislavery law that gave the "new slavery" explicit legal sanction. Black freedom movement activists, thinkers, and organizers did more than call out this breathtaking betrayal of abolitionist principles: they dedicated themselves to the eradication of slavery on whatever forms it assumed on the global stage and developed an expansive vision of human freedom. This timely and important work reminds us that the resurgence of today's Black freedom movements is a manifestation and continuation of the tradition and efforts of these early Black leaders and abolitionists - an important chapter in the history of antislavery and the ongoing Black freedom struggle.