The Secret World of Sleep: How the Nighttime Brain Creates Consciousness

Most of us have some vague impression of the scientific explanations for sleep%E2%80%94resting, reorganizing our thoughts, etc.%E2%80%94but probably no real idea of why or how these things work; luckily Lewis is able to fill in the gaps in her concise and accessible book. As director of Sleep and Memory Lab at the University of Manchester, she is an authority in field and presents her research in an easy-to-read manner. The book starts with the basics: what is sleep? Lewis offers a working "loose definition," is that it's "an inactive time during which an organism responds less than usual when poked or disturbed, but from which it can be roused if danger threatens." From there she explores several possible "reasons" for sleep, including the way the sleeping brain bolsters our ability to remember things (like someone's name, or the way to a friend's house) by something called "memory rehearsal," a reenactment of the information at the "neural level." Lewis also confirms a truth we may have known intuitively, if perhaps had yet to see confirmed by scientific study: "sleep-deprived people are more easily frustrated, intolerant, unforgiving, uncaring, and self-absorbed than they would be if they were properly rested." (Sept.)