Precision medicine is the opposite of one-size-fits-all therapy. An emerging approach to preventing or treating diseases, it factors in individual variability in genes, environment, and lifestyle in order to custom-tailor treatment. Although it is still far from becoming a routine part of clinical medicine, the Precision Medicine Initiative unveiled by President Obama in January 2015 is designed to accelerate progress, initially in cancer and eventually in countless other diseases. “Much of the necessary methodology remains to be invented and will require the creative and energetic involvement of biologists, physicians, technology developers, data scientists, patient groups, and others,” writes NIH Director Francis Collins in the New England Journal of Medicine. Where do we expect precision medicine to lead in five years? In a decade?