The underlying question of this book is referred to as “Yali’s Question.” It is a question that was asked of Jared Diamond by a New Guinean named Yali. It is stated on p. 14 of the paperback edition of the book. What Yali asked was
Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?
“Cargo” was the term that New Guineans used for all of the material goods that Europeans and people of European descent like Australians and Americans had.
The question, then, is essentially a question of why Europeans and their descendants became so rich and powerful. By the time that Yali asked this question in the early 1970s, Europeans and their descendants completely dominated the world. They were by far the richest and most powerful people in the world. The underlying question of this book is the question of how this came to be. Diamond spends the rest of the book trying to answer Yali’s question.