Lee Ji-yoo, who has invited readers to vast worlds such as volcanoes, Earth, and universe and fascinatingly explained diverse types of scientific and historical knowledge in previous books, leads us to the world of the human body this time. Starting from common questions, this volume explicates the composition and operation of the body on children’s eye level, in a readily comprehensible manner. Part 1 deals with cells, which are the smallest units constituting the body. Part 2 addresses sensory organs, which receive external stimuli through the senses of sight, hearing, touch, taste, and smell. Part 3 explains the skeleton, which buttresses the body, and the skin, which covers the body. Part 4 guides readers to the roles of internal organs such as the circulatory and digestive systems. Finally, Part 5 examines in a multifaceted way the brain, which can be seen as the headquarters of the body. As such, this work surely will go beyond simply satisfying young readers’ curiosity about the human body and help them to care for and maintain their own bodies in a healthy and independent way based on the correct understanding of the body.