Book excerpt: In Twenty Years of Life, Suzanne Bohan exposes the ugly truth that health is largely determined by zip code. Life expectancies in wealthy versus poor neighborhoods can vary by as much as twenty years. Bohan chronicles a bold experiment to challenge that inequity. The California Endowment, one of the nation's largest health foundations, is upending the old-school, top-down charity model and investing $1 billion over ten years to help distressed communities advocate for their own interests. With compassion and insight, Bohan shares stories of students and parents, former street shooters, urban farmers, and a Native American tribe who are tapping into their latent political power to make their neighborhoods healthier. Their stories will fundamentally change how we think about the root causes of disease and the prospects for healing.