Book excerpt: Pharmacogenomics is the basis of personalized medicine which will be the medicine of the future. Through both reducing the numbers of adverse drug reactions and improving the use of existing drugs in targeted populations, pharmacogenomics represents a real advance on traditional therapeutic drug monitoring. Pharmacogenomics in Clinical Therapeutics provides an introduction to the principles of pharmacogenomics before addressing the pharmacogenomic aspects of key therapeutic areas such as warfarin therapy, cancer chemotherapy, therapy with immunosuppressants, antiretroviral therapy, and psychoactive drugs. It also includes methods of pharmacogenomic testing and the pharmacogenomic aspects of drug–drug interactions. From a team of expert contributors, Pharmacogenomics in Clinical Therapeutics is a comprehensive overview of the current state of pharmacogenomics in pharmacotherapy for all clinicians, pharmacologists and clinical laboratory professionals. It is also a guide for practicing clinicians and health care professionals to the basic principles of pharmacogenomics, laboratory tests currently available to aid clinicians, and the future promise of this developing field.