Why We Sleep Unlocking the Power of Sleep and Dreams By Matthew Walker "Why We Sleep" by Matthew Walker emphasizes the profound importance of sleep for overall health and well-being. The book argues that sleep is not merely a passive state but an active process crucial for learning, memory consolidation, emotional regulation, and even preventing chronic diseases like cancer, Alzheimer's, and diabetes. Walker highlights the detrimental effects of sleep deprivation on cognitive function, mood, and physical health, advocating for prioritizing quality sleep as a key factor in improving one's life.