Brain science offers essential clues for understanding who we are and the people around us. When my daughter was very young, she got frustrated because she couldn't memorize a web address. So I told her, "People naturally can't remember more than seven items at once." She replied, "Oh, so it's normal that I can't memorize this," and she understood right away. Another time, my younger daughter complained that her parents treated her unfairly compared to her older sister. So I called both girls together and said, "Our brains have a region called the 'insula' that compares whether parents treat siblings equally. So no matter how hard you try not to feel jealous, that's just how our brains work — don't feel guilty about comparing yourself to your sister, and if something feels unfair, just tell Mom and Dad." Hearing this, the girls understood the situation and even made up with each other. Watching moments like these made me want to write a children's or young-adult book someday. And if I could only publish one children's book, I wanted it to be one that teaches kids the brain science behind understanding our own hearts and minds. We never really learn about brain science until after high school graduation — yet it holds vital clues for understanding who we are, why our friends behave the way they do, and why our communities and society function as they do. Teaching children brain science early can help them manage their emotions better and deepen their empathy for why others act the way they do. With the wish to teach brain science to kids in a fun and exciting way, I began planning this book. If I had to describe the Human Exploration Report series in one phrase... it's like a jukebox of curiosity. Most of the worries children have growing up can actually be answered by understanding the brain. 'Why do I feel this way sometimes? Why do I sometimes fight with others, fail to control my impulses, or want to do exactly the things I'm told not to? Why does my friend act that way? Why do my parents say these things to us?' Most of the questions we had as children can largely be explained by teaching kids about the mind and the brain that holds it. That's why I think of the Human Exploration Report series as a jukebox for the curiosities and questions we truly wonder about. You put in the question you've always had, and out comes a wonderful answer through brain science — that's the kind of jukebox it is. I hope children come to see brain science not as some difficult academic subject, but as a map for understanding themselves and their friends. Fascinating topics about being human continue throughout the series — 'appearance,' 'memory,' 'emotions,' 'puberty,' 'the senses,' and more. Everyone is sensitive about their appearance. It seems like such an obvious thing, but it's actually quite curious when you think about it — because to our eyes, monkeys or gorillas all look pretty much alike. Yet among themselves, they can tell in fine detail which monkey looks more impressive or attractive, comparing and competing with one another. We're no different. Viewed through an alien's eyes, our eyes, noses, and mouths might all look similar too — so why do we obsess so much over who looks prettier or more handsome? It might seem strange. Of course, this can lead us toward an unhealthy obsession with looks, but in the process, we also learn to read others' emotions delicately and understand people through their expressions — all of this seems to be wrapped up in how we think about appearance. I hope that by exploring why humans are so preoccupied with appearance, children can come to understand how empathy for others develops. With that hope, I boldly...