"Karl Deisseroth has spent his life pursuing truths about the human mind, both as a practicing clinical psychiatrist and as a researcher who created the revolutionary field of optogenetics, which allows us to decipher the brain's inner workings using light. In his first book, Projections, he combines his groundbreaking access to the brain's inner circuitry with a deep empathy for his patients to examine what mental illness can reveal about the mind...