Harari's work places human history within a framework, with the natural sciences setting limits for human activity and social sciences shaping what happens within those bounds. The academic discipline of history is the account of cultural change.

Harari surveys the history of humankind from the Stone Age up to the 21st century, focusing on Homo sapiens. He divides the history of H. sapiens into four major parts:[3]

The Cognitive Revolution (c. 70,000 BCE, the start of behavioral modernity when imagination evolved in H. sapiens).
The (first) Agricultural Revolution (c. 10,000 BCE, the development of agriculture).
The Unification of Humankind (c. 34 CE, the gradual consolidation of human political organizations towards globalization).
The Scientific Revolution (c. 1543 CE, the emergence of objective science).
Harari's main argument is that H. sapiens came to dominate the world because they are the only animal that can cooperate flexibly in large numbers. He argues that prehistoric H. sapiens were a key cause of the extinction of other human species such as the Neanderthals and numerous other megafauna. He further argues that the ability of H. sapiens to cooperate in large numbers arises from its unique capacity to believe in things existing purely in the imagination, such as gods, nations, money and human rights. He argues that these beliefs give rise to discrimination – whether racial, sexual or political – and it is potentially impossible to have a completely unbiased society. Harari claims that all large-scale human cooperation systems – including religions, political structures, trade networks and legal institutions – owe their emergence to H. sapiens' distinctive cognitive capacity for fiction.[4] Accordingly, Harari describes money as a system of mutual trust and political and economic systems as similar to religions.