Yu Huan 
Healthcare Revolution 3–Prepare to have deep sleep 

This book is an exciting instructor for improvement of sleep quality. It is designed to help the readers improve sleep quality and improve the state of physical and mental fatigue. It will open a treasure box hiding the secret of sleep, simply answer all the questions in sleep and teach you how to overcome obstacles and fall into a sweet sleep, so as to improve the life quality. In a sense, this book will be a indispensable key to interpretation of the mystery of sleep and improvement of sleep quality.