Who hasn't experienced the restorative power of a good night's sleep? Sleep of sufficient quantity is an integral element of a healthy lifestyle. Lacking it, both physical and emotional well-being suffer. Do you wonder how much sleep is too much? How to beat insomnia? Why you dream and what yours dreams really mean? TIME takes you into The Science of Sleep, an active field of research with great relevance to health and well-being. New research shows that a good night's rest isn't a luxury, it's critical for the health of your brain as you age. We provide you with “The 9 New Sleep Rules” for better sleep, tips to “Sleep Like a Pro” from athletes to CEOs, and ways to “Wake Up Your Creativity” even in your sleep. We answer the question “Can You Sleep Yourself Slim?” and show how your sleep routine plays a role in your weight loss journey. “The Truth About Sleeping Pills” is our comprehensive pros-and-cons guide to various types of sleeping aids. Finally, we present a concluding photo essay that illustrates “A World of Slumber” with portraits of sleeping individuals around the globe.