Slavery is one of the most tragic institutions in human history. It has caused intense pain to people and societies around the world. What are the origins of this institution? Why has it happened where it happened? Economic history has taken a new causal approach to these questions trying to understand the fundamental forces that govern this institution. This causal understanding allows economists to understand the effects of slavery in today's socio-economic outcomes. In this lecture, Dr. Juan Moreno-Cruz presents some of the new insights developed in the last 10 years and highlights areas of future research.