Pulitzer Prize-winning, New York Times reporter Matt Richtel presents a cutting-edge account of scientific discoveries that promise to revolutionize the practice of medicine - and improve our lives immeasurably - in An Elegant Defense: The Extraordinary New Science of the Immune System: A Tale in Four Lives . The immune system impacts every aspect of our lives, including sleep, mood, fitness, nutrition, brain function, and aging, and is the ultimate key to wellness and longevity.