The weakness of single-factor theories is also their virtue: they require us to consider phenomena that we might otherwise ignore or deprecate. The history of all hitherto existing societies is not the history of class struggle; the origins of China are not to be explained exclusively with reference to riparian infrastructure; and the development of American democracy is not solely the consequence of our frontier life. No complex movement or event can really be reduced to one driving force, but it is nonetheless instructive to view events through a single lens.

In that vein, tech engineer and independent researcher Jens Heycke asks us to understand the rise of the Roman Empire, the fall of the Ottomans, the Spanish conquest of Mexico, the Rwandan genocide, and sundry other events through the single lens of multiculturalism. Out of the Melting Pot, Into the Fire: Multiculturalism in the World’s Past and America’s Future is a call to revive a singular American identity. By “multiculturalism,” Heycke means extreme ethnic and cultural pluralism, in which various populations live side by side in a jumble without ever coming together around shared mores or traditions. He contrasts this approach with the “melting pot,” in which a strong sense of cultural unity smooths out the differences among new arrivals and assimilates them to the dominant local culture.