Why We Sleep* is a 2017 popular science book by neuroscientist and sleep expert Matthew Walker. It explores the science of sleep and the consequences of sleep deprivation on cognitive function, health, safety, and business. Walker argues that sleep is a cure-all for various conditions, including depression, anxiety, and unhappiness. He also emphasizes the importance of sleep for young minds, suggesting that early school start times are detrimental to teenagers' mental health