100,000 years ago, Homo sapiens was one of several human species on the planet that had nothing particularly special about it. But about 70,000 years ago, Homo sapiens underwent a change in its cognitive abilities, and it became the dominant species—one that influences the ecosystem. Yuval Harari’s book explores how humans became the rulers of the planet, what happened to other human species, and how various historical events unfolded that affected the development of society.