Humans are social animals. They cannot live entirely alone. Studying human history means exploring how humans have related to each other, and how those relationships have changed over time. It is these relationships, and the ability of humans to exchange and share information, that make us distinctive from other species. So human relations with each other are naturally at the core of world history.

How humans have treated each other within families, in times of war, in politics, and in commerce have been the meat and drink of historical scholarship. So have relationships between slaves and their masters, rulers and their subjects, men and women, one ethnic group and another. And in investigating these relationships, world history is no different from most other types of history. But world history tries to ask these questions about all humans. How did humans in one part of the world affect humans in very different parts of the world, through exchanges of goods, diseases, or religious ideas and technologies? Were there always states in human history? Or cities? Was there always war? By raising such questions, world history studies wrestles with the entire range of relationships of which humans are capable.

World history is also about intimate relationships. What was it like to live in a small community of hunters and gatherers? Has the very nature of human relationships changed over time? World History, in short, is about what it means to be human, and, because of its scope, it raises these questions in ways that other approaches to history usually do not because they look at the past only on relatively small scales.