Over the course of her first semester at Spelman College, Georgianne Thomas went from sheltered freshman to foot soldier on the frontlines of a movement that would change the world.

They, along with William K. Bagby, Clark & Grubb, Fields & Gresham, Zachariah Rice, S.H. Griffin, W.H. Henderson, Inman, Cole & Co., and the Ponder brothers, all trafficked in lives across 20 slave ...