concerns within the pharmaceutical industry about generating data that might be difficult to interpret in a regulated environment. There is also a growing apprec- tion for the challenges in translating this new information into clinical utility, including scientific, commercial, ethical, and policy challenges. Pharmacogenomics and Personalized Medicine, which is part of the Methods in Pharmacology and Toxicology series, comprises chapters on selected aspects of pharmacogenomics and personalized medicine. Our overall intent is to assist both novice and experienced investigators in understanding the current scientific ch- lenges in applying PGx to discovery and clinical development and in making app- priate decisions to engage in and interpret PGx research. Designed to share the experiences of leading experts in the field, the book is a useful guide for conducting PGx research—from discovery to the market, but we also aim to present a realistic perspective on the challenges, practicalities, and obstacles in applying pharmac- enomics. Generally, the book avoids statements such as “Pharmacogenomics is going to revolutionize the practice of medicine,” which are neither realistic nor particularly useful to anyone. The book presents an industry perspective on the implementation of PGx in research and development, in drug discovery, and in clinical trials, including rec- mendations for a systematic approach for assessing the feasibility and added value of PGx studies in clinical trials.