They call themselves "sensitives." Over fifty million Americans endure a mysterious environmental illness that renders them allergic to chemicals. Innocuous staples from deodorant to garbage bags wreak havoc on sensitives. For them, the enemy is modernity itself.

No one is born with EI. It often starts with a single toxic exposure. Then the symptoms hit: extreme fatigue, brain fog, muscle aches, inability to tolerate certain foods. With over 85,000 chemicals in the environment, danger lurks around every corner. Largely ignored by the medical establishment and dismissed by family and friends, sensitives often resort to odd ersatz remedies, like lining their walls with aluminum foil or hanging mail on a clothesline for days so it can "off-gas" before they open it.

Broudy encounters Brian Welsh, a prominent figure in the EI community, and quickly becomes fascinated by his plight. When Brian goes missing, Broudy travels with James, an eager, trusting sensitive to find Brian, investigate this disease, and delve into the intricate, ardent subculture that surrounds it. Their destination: Snowflake, the capital of the EI world. Located in eastern Arizona, it is a haven where sensitives can live openly without fear of toxins or the judgment of insensitive "normals."

While Broudy's book is wry, pacey, and down-to-earth, it also dives deeply into compelling corners of medical and American history. He finds telling parallels between sensitives and their cultural forebears, from the Puritans to those refugees and dreamers who settled the West. Ousted from mainstream society, these latter-day exiles nonetheless shed bright light on the anxious, noxious world we all inhabit now.