This book is a fun history of sleep and is also philosophical, which is based on the dialogue between the author Wang Meng and the famous doctor Guo Xiheng about sleep. As sleeping problems affect people's life, work and health more and more, the author and the doctor shares fun stories and their insights about sleep from the field they are good at. Mr. Wang Meng starts from his life experiences and tells his fun experiences that he had insomnia when he was young yet becomes easy to fall asleep when he gets old. And he also quotes the philosophy of Zhuangzi and brings up that insomnia is a false concept. Professor Guo Xiheng analyzes the biological rhythm of sleep from classic clinical cases from his 30 years of career in medicine and tries to relieve the anxiety of people with insomnia in scientific and psychological ways.