The greatest computer ever built is less than 7 in. long and weighs less than 3 lb. It has no moving parts and makes not a sound. And yet it is the home of dreams, of songs, of wisdom, of philosophy, of love, of awareness itself. The greatest computer ever built is, of course, the human brain. For almost as long as we've been thinking creatures, we've wondered about the galaxy of experiences, emotions and insights that lives within every one of us. You have your heart; you have your limbs. You are your brain. The editors and writers of TIME invite you to explore that wondrous place that is the seat of your being. What does science tell us about how we learn, how we mature, why our minds grow old? How does memory work--and why does it so often fail to work? How can babies learn multiple languages before they're 5 years old, while adults must struggle for years to master a single new one? What does it mean to be a genius? What does it mean merely to be conscious? These and other questions are being explored by investigators across the sciences, and TIME has gone out in search of them. At labs and universities around the world, researchers are gaining new understanding of the differences between the brains of men and women, the neurochemical magic behind feelings of romance, the mystery of good and evil. They are learning new things about addictions and disorders and the myriad ways minds can break down. And they are learning how to fix them too. The Brain: A User's Guide will give you a whole new view of how your brain works and ways you can use that understanding to help yourself become wiser, happier, even healthier. You will never think of the world inside your head the same way again.