Personalized medicine, which simply means selection of treatment best suited for an individual, involves integration and translation of several new technologies in clinical care of patients. The scope is much broader than indicated by the term genomic medicine because many non-genomic factors are taken into consideration in developing personalized medicine. Basic technologies for personalized medicine, of which molecular diagnostics has the biggest share, are mentioned briefly and appropriate references are given for further information. Commercial aspects are discussed briefly in a chapter and detailed analysis of markets and companies involved in personalized medicine is presented in a special report on this topic. There is increasing interest in personalized medicine. Considerable advances have taken place in molecular biology and biotechnology to make personalized medicine a viable option, but some misconceptions still exist, both in the academic and commercial sectors. There is lack of a suitable source of information that provides both the fundamentals as well as applications of personalized medicine. As the latest version of the first monograph on personalized medicine published in 1998, this volume, Textbook of Personalized Medicine, summarizes the author’s efforts during the past decade, as well as reviews selected studies done during this period in a readable format for the physicians and scientists. It is hoped that physicians, pharmacists, scientists and interested lay readers with basic scientific knowledge will find this book useful.