In December 2010, scientists discovered a fragment of a finger bone in an isolated cave in Siberia. To their surprise, the bone contained neither Homo sapiens nor Neanderthal DNA. The DNA came from a previously unknown species of hominids—the Denisovans—who shared a common ancestor with both Neanderthals and Homo sapiens.

This discovery reshaped everything we thought we knew about the “out of Africa” theory. Scientists initially believed that Homo erectus inhabited much of Asia, but looking at Denisovan fossils and the genealogy of native populations in the Philippines reveals that the Denisovans made up a vast population, occupying much of East Asia and Oceania.

But who were the Denisovans? How did they live? What did they look like? Paleoanthropologist Silvana Condemi and science journalist François Savatier tell the Denisovans’ story in The Secret World of Denisovans. Leading us through the excavation of Denisova cave, the sequencing of the Denisovan genome, and recent research on Denisovan fossils, Condemi and Savatier uncover how the Denisovans migrated to Asia, who they interacted with along the way, and why traces of Denisovan DNA can be found in modern-day humans. By studying the story of the Denisovans, we can better understand how humans evolved and populated the globe—and how we are more closely related to our prehistoric ancestors than we might think.