“Why We Sleep is an important and fascinating book…Walker taught me a lot about this basic activity that every person on Earth needs. I suspect his book will do the same for you.” —Bill Gates

A New York Times bestseller and international sensation, this “stimulating and important book” (Financial Times) is a fascinating dive into the purpose and power of slumber.

Sleep is one of the most important but least understood aspects of our life, wellness, and longevity. Until very recently, science had no answer to the question of why we sleep, or what good it served, or why we suffer such devastating health consequences when we don't sleep. Compared to the other basic drives in life—eating, drinking, and reproducing—the purpose of sleep remained elusive.

An explosion of scientific discoveries in the last twenty years has shed new light on this fundamental aspect of our lives. Now, preeminent neuroscientist and sleep expert Matthew Walker gives us a new understanding of the vital importance of sleep and dreaming. Within the brain, sleep enriches our ability to learn, memorize, and make logical decisions. It recalibrates our emotions, restocks our immune system, fine-tunes our metabolism, and regulates our appetite. Dreaming mollifies painful memories and creates a virtual reality space in which the brain melds past and present knowledge to inspire creativity.

Walker answers important questions about sleep: how do caffeine and alcohol affect sleep? What really happens during REM sleep? Why do our sleep patterns change across a lifetime? How do common sleep aids affect us and can they do long-term damage? Charting cutting-edge scientific breakthroughs, and synthesizing decades of research and clinical practice, Walker explains how we can harness sleep to improve learning, mood, and energy levels; regulate hormones; prevent cancer, Alzheimer’s, and diabetes; slow the effects of aging; increase longevity; enhance the education and lifespan of our children, and boost the efficiency, success, and productivity of our businesses. Clear-eyed, fascinating, and accessible, Why We Sleep is a crucial and illuminating book.

"Sleep is one of the most important but least understood aspects of our life, wellness, and longevity ... An explosion of scientific discoveries in the last twenty years has shed new light on this fundamental aspect of our lives. Now ... neuroscientist and sleep expert Matthew Walker gives us a new understanding of the vital importance of sleep and dreaming"--Amazon.com.

"Why We Sleep is simply a must-read. World-renowned neuroscientist and sleep expert Matthew Walker takes us on a fascinating and indispensable journey into the latest understandings of the science of sleep. And the book goes way beyond satisfying intellectual curiosity, as it explores the cognitive, health, safety and business consequences of compromising the quality and quantity of our sleep; insights that may change the way you live your life. In these super-charged, distracting times it is hard to think of a book that is more important to read than this one."
—Adam Gazzaley, co-author of The Distracted Mind, founder and executive director of Neuroscape, and Professor of Neurology, Physiology, and Psychiatry at University of California, San Francisco

“Most of us have no idea what we do with a third of our lives. In this lucid and engaging book, Matt Walker explains the new science that is rapidly solving this age-old mystery. Why We Sleep is a canny pleasure that will have you turning pages well past your bedtime.”
—Daniel Gilbert, professor of psychology at Harvard and author of Stumbling on Happiness

"In Why We Sleep, Dr. Matt Walker brilliantly illuminates the night, explaining how sleep can make us healthier, safer, smarter, and more productive. Clearly and definitively, he provides knowledge and strategies to overcome the life-threatening risks associated with our sleep-deprived society. Our universal need for sleep ensures that every reader will find value in Dr. Walker's insightful counsel."
—Mark R. Rosekind, Ph.D., former NHTSA Administrator, NTSB member, and NASA scientist