Adherents of this five phase system of palmistry believed and still do that appearances in the hand can reveal the san hou or three periods. In other words, one can examine a person's past (xian zhen), the present (zai zhen), and their future (lai zhen). One can also read the hands for information about the four imports or si tong. This means that the appearances of the hands can reveal the mind (xin) or personality, the body (shen), the emotions and thoughts (yi), and the qi which unifies all these three. Thus it is clear that practitioners of this five phase system of Chinese palmistry did diagnose the physical predispositions and ailments of their subjects.

Numerous other important Chinese books on palmistry were written in succeeding dynasties. For instance, Chen Dan-ye published his well-known book on palmistry, the Xiang Li Heng Zhen (Mutual Appearances & Their Principles for Measuring the Truth), in the Qing Dynasty (1644-1911 ce), and Gao Wei-qing compiled the Shen Xiang Hui Pian (Collected Writings on Divine Mutual Appearances) in 1843. In terms of the medical literature, Lin Zhi-han's Si Zhen Jue Wei (Secrets of Success in the Four Examinations in Minute Detail) published in 1723 and Zhou Xue-hai's Xing Se Wai Zhen Jian Mo (Easy Study Form & Color External Examination) published in 1894 both contained abundant information on hand diagnosis.

Beginning in the seventeenth century, palmistry began to draw the attention of Chinese practitioners of various of the emerging modern sciences. Anatomists were the first to become interested in palmistry but since have been followed by anthropologists, biologists, and geneticists. These scientists have observed, analyzed, and studied the lines on the palm and have made a number of important contributions to this body of knoweldge. Within the last 20-30 years in particular, the medical field has begun to show widespread interest in this system of correspondences.

By exploring palmistry from the viewpoint of modern medicine and genetics, further understanding has been gained in the relationship between the lines on the hand and disease. In addition, by utilizing scientific technology, new developments have occurred in the study of palmistry. In China today, biologist, psychologists, and sociologists as well as the above-mentioned anthropologists, geneticists, and physicians are all engaged in substantiating the age-old wisdom on human health and disease contained in Chinese palmistry.

Thus this book is a combination of age-old Chinese lore and modern scientific findings. Some of the indications given in this book are based on yin yang theory, the five phases, or the eight trigrams. Other indications are based on modern clinical observation. This makes modern Chinese medical palmistry a unique blend of ancient and modern knowledge.

Who and How to Use Chinese Medical Palmistry
The indications represented in this book can be used by lay people to help determine their individual organic strengths and weaknesses or, in other words, their constitutional predisposition. Knowing how one may tend to become ill, readers of this book can then alter their diet and lifestyle or seek preventive treatment so as to prevent tendencies from becoming realities. Ever since the Warring States Period and the writing of the Huang Di Nei Jing (The Yellow Emperor's Inner Classic), prevention has been the highest form of medicine within TCM, and Chinese medical palmistry is well suited to become one of the diagnostic cornerstones of the preventive medicine of the future.