Book excerpt: A groundbreaking tour of the human mind that illuminates the biological nature of our inner worlds and emotions, through gripping, moving—and, at times, harrowing—clinical stories “[A] scintillating and moving analysis of the human brain and emotions.”—Nature “Beautifully connects the inner feelings within all human beings to deep insights from modern psychiatry and neuroscience.”—Robert Lefkowitz, Nobel Laureate Karl Deisseroth has spent his life pursuing truths about the human mind, both as a renowned clinical psychiatrist and as a researcher creating and developing the revolutionary field of optogenetics, which uses light to help decipher the brain’s workings. In Projections, he combines his knowledge of the brain’s inner circuitry with a deep empathy for his patients to examine what mental illness reveals about the human mind and the origin of human feelings—how the broken can illuminate the unbroken. Through cutting-edge research and gripping case studies from Deisseroth’s own patients, Projections tells a larger story about the material origins of human emotion, bridging the gap between the ancient circuits of our brain and the poignant moments of suffering in our daily lives. The stories of Deisseroth’s patients are rich with humanity and shine an unprecedented light on the self—and the ways in which it can break down. A young woman with an eating disorder reveals how the mind can rebel against the brain’s most primitive drives of hunger and thirst; an older man, smothered into silence by depression and dementia, shows how humans evolved to feel not only joy but also its absence; and a lonely Uighur woman far from her homeland teaches both the importance—and challenges—of deep social bonds. Illuminating, literary, and essential, Projections is a revelatory, immensely powerful work. It transforms our understanding not only of the brain but of ourselves as social beings—giving vivid illustrations through science and resonant human stories of our yearning for connection and meaning.