Living in harmony with the natural world and cultivating the virtues of simplicity, honor, integrity, and respect for all things form the foundation of Taoist spirituality. In this book, Wong presents and explains three classic texts that represent the three traditional levels of the Taoist teachings -- Outer, Inner, and Secret. The Outer teachings are concerned with understanding the Tao as Manifested in Nature and Society. The Inner teachings familiarize the practitioner with the energetic structure of the human body and introduce methods of stilling the mind and cultivating internal energy for health and longevity. The Secret teachings describe the highest level of internal-alchemical transformations within the body and mind for attaining immortality. The three texts that Wong has translated here provide a fine overview of these spiritual teachings. Two of the texts, Understanding the Mysteries and The Secret Treatise of the Great Mystery are from the teachings of Southern Complete Reality Taoism, a school of internal-alchemical Taoism.