This audiobook is narrated by a digital voice.

The modern world is experiencing an unprecedented rise in autoimmune diseases that has largely escaped public attention despite affecting millions of people and imposing enormous costs on healthcare systems and individual lives. These conditions, where the immune system mistakenly attacks the body's own tissues, have increased dramatically over the past several decades in ways that cannot be explained by better diagnosis alone, suggesting that fundamental changes in our environment and lifestyle are triggering widespread immune system dysfunction.

Type 1 diabetes, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, and dozens of other autoimmune conditions have shown consistent increases in incidence across developed countries, with some conditions doubling or tripling in frequency over periods as short as two decades. This rapid increase in autoimmune disease represents one of the most significant health trends of the modern era, yet it receives relatively little public attention compared to other health issues that affect fewer people.

The hygiene hypothesis suggests that reduced exposure to microorganisms in early life may compromise immune system development, leading to increased susceptibility to autoimmune diseases later in life. The widespread use of antibiotics, antimicrobial products, and sanitizers may be disrupting the normal development of immune tolerance while the reduction in infectious diseases that once challenged developing immune systems may be leaving them poorly calibrated to distinguish between harmful invaders and the body's own tissues.