Why We Sleep

Why We Sleep asks why we need sleep. It looks at how sleep shapes health and lifespan. Matthew Walker argues that modern life puts too little value on sleep. He looks at links between too little sleep and Alzheimer's. He also looks at links with cancer, obesity and diabetes. Sleep's purpose long puzzled scientists, unlike that of other basic needs. Walker asks why this was so.

This science book shares sleep research with the general reader. Walker is a professor who studies sleep. He draws on two decades of work. He uses studies of humans and animals to explain sleep's role. He covers REM sleep and how sleep changes with age. He also looks at the effects of caffeine and alcohol.