The story of a young entrepreneur who gambles on the risky science of gene therapy to try to save his brother's life. In this dramatic and suspenseful narrative, Jonathan Weiner gives us a remarkable portrait of science and medicine today. We learn about gene therapy, stem cells, brain vaccines, and other novel treatments for such nerve-death diseases as ALS, Alzheimer's, and Parkinson's-diseases that afflict millions, and touch the lives of many more.