As part of Black History Month, Book of the Day brings you an interview with author Isabel Wilkerson. She followed her book about The Great Migration, The Warmth of Other Suns, with another that looks at why it happened. Caste argues that caste and not racism is actually what Black people were fleeing when they left the Jim Crow South. Wilkerson told Throughline's Ramtin Arablouei and Rund Abdelfatah that the term racism is rooted in hate but caste is about "power and how those other groups manage and navigate and seek to survive in a society that's created with this ranked hierarchy."