Guns, Germs, and Steel is a work of synthesis. Diamond tries to bring together the work of scholars in such disciplines as anthropology, evolutionary biology (his own field), and history in order to craft an argument. He is trying to explain why societies developed at different rates and the consequences of this fact. It is the breadth of the book, along with the staggering amount of research it entails, that is its greatest strength, but it also opens Diamond to criticism from specialists. Many readers will struggle with his characterization of, for example, historical theories of social development. He does not engage, for example, with the historical theory of the "Great Divergence" developed by historian Kenneth Pomerzntz, which puts the Industrial Revolution at the forefront as opposed to the much earlier development of agriculture. This is related to another often-cited criticism of Guns, Germs, and Steel. Many critics found the book overly deterministic in its claims that biological and ecological factors essentially mapped out the future of societal and technological development. They think he understates the role of human action (called "agency" by scholars) in the development of societies. This is an especially pertinent critique because it seems to ignore the fact that imperialism, colonialism, and exploitation would then in some ways be natural and unavoidable consequences of the biologically determined process of human development. Diamond actually addresses this second critique directly in the next popular book he published, titled Collapse. Other critics argue that by focusing on the inequality between human societies, Diamond ignores the importance of the inequalities within them. They claim that he ignores the diversity of peoples that he categorizes into races. Still, Guns, Germs, and Steel is a rare example of a work of popular scholarship that prompted serious and important debate within the scholarly community, and even its critics have credited Diamond's ability to present complex scholarly debate in an accessible way. While very broad and sweeping, Guns, Germs and Steel is remarkably focused and "readable." Its rejection of the concept that one culture or society is inherently superior to others is one that all scholars, and hopefully a wider readership, can accept.