Content Warning: This section of the guide includes discussion of illness, death, child death, ableism, and racism.

The book begins with the story of Scottish scientist James Watt, an inventor who helped improve the efficiency of steam engines in the late18th century. Watt became focused on finding a chemical treatment for a lung disease known at the time as phthisis, or consumption. After losing his daughter, Jessy, to the disease, Watt wanted to save his son, Gregory. Watt devised a machine that administered nitrous oxide into the lungs, but it failed, and Gregory died in 1804.

A century later, author John Green’s great-uncle Strokes Goodrich, who experienced many diseases throughout his lifetime, contracted phthisis, then more commonly known as tuberculosis (TB). He lived in a sanatorium in North Carolina with many other TB patients until his death in 1930 at the age of 29.

Green jumps to the present, two centuries after the death of Gregory Watt. He reports that TB is still the world’s deadliest infectious disease, despite existing cures for TB. They remain inaccessible in the parts of the world where the disease has the greatest impact, leading to widespread death.