Could a few fleas really change the world? In the early 1300s, the world was on the brink of change. New trade routes in Europe and Asia brought people in contact with different cultures and ideas, while war and rebellions threatened to disrupt the lives of millions. Most people lived in crowded cities or as serfs tied to the lands of their overlords. Conditions were filthy, as most people drank water from the same sources they used for washing and for human waste. In the cramped and rat-infested streets of medieval cities and villages, all it took were the bites of a few plague-infected fleas to start a pandemic that killed roughly half the population of Europe and Asia. The bubonic plague wiped out families, villages, even entire regions. Once the swollen, black buboes appeared on victims’ bodies, there was no way to save them. People died within days. In the wake of such devastation, survivors had to reevaluate their social, scientific, and religious beliefs, laying the groundwork for our modern world. The Black Death outbreak is one of world history’s pivotal moments.

We hear plenty about the widening income gap between the rich and the poor in America and about the expanding distance separating the haves and the have-nots. But when detailing the many things that the poor have not, we often overlook the most critical—their health. The poor die sooner. Blacks die sooner. And poor urban blacks die sooner than almost all other Americans. In nearly four decades as a doctor at hospitals serving some of the poorest communities in Chicago, David A. Ansell, MD, has witnessed firsthand the lives behind these devastating statistics. In The Death Gap, he gives a grim survey of these realities, drawn from observations and stories of his patients. While the contrasts and disparities among Chicago’s communities are particularly stark, the death gap is truly a nationwide epidemic—as Ansell shows, there is a thirty-five-year difference in life expectancy between the healthiest and wealthiest and the poorest and sickest American neighborhoods. If you are poor, where you live in America can dictate when you die. It doesn’t need to be this way; such divisions are not inevitable. Ansell calls out the social and cultural arguments that have been raised as ways of explaining or excusing these gaps, and he lays bare the structural violence—the racism, economic exploitation, and discrimination—that is really to blame. Inequality is a disease, Ansell argues, and we need to treat and eradicate it as we would any major illness. To do so, he outlines a vision that will provide the foundation for a healthier nation—for all. Inequality is all around us, and often the distance between high and low life expectancy can be a matter of just a few blocks. But geography need not be destiny, urges Ansell. In The Death Gap he shows us how we can face this national health crisis head-on and take action against the circumstances that rob people of their dignity and their lives.