This imaginative and friendly guidebook invites curious young readers to explore the incredible world of their minds—described as an invisible backpack filled with emotions, thoughts, questions, and imagination. Unlike dense textbooks, it uses clear, playful language and vivid examples to explain how the brain builds memories, reacts to stories, dreams, emotions, and even questions like whether computers can think or animals feel. Along the way, kids learn about empathy, illusions, creativity, and the mysteries of life and death. Each chapter includes fun "Try It Now" activities, like drawing feelings or imagining sideways gravity, to help kids experience brain science firsthand. The book also encourages readers to keep asking big questions, reminding them that science and philosophy are ongoing adventures. With a focus on understanding and steering their own minds, this book empowers young explorers to become kinder, wiser, and endlessly curious about themselves and the world around them.