It is a great pleasure to respond to the invitation to write a foreword for this book. With a worldwide increase in an aging population, the practice of medicine is increasingly focused on elderly patients with chronic diseases and episodic acute exacerbations rather than the previous model of acute disease management only. As nephrologists around the world deal with millions of elderly individuals, many of whom are classified as suffering from chronic kidney disease in stages 2–5, they are, of necessity, practicing geriatrics without specific training or previous exposure in this field. Therefore, most nephrologists, as well as dealing with new types of clinical presentations, and geriatric evaluation tools, will face the difficulties of reaching the treatment targets specific to geriatric patients. These geriatric targets include, in addition to the usual diagnosis and medical or surgical treatment for young adults, the recuperation of the ability to perform activities of daily living, which are often partially or totally lost in renal disease. Apart from these clinical difficulties, physicians will also face enormous ethical challenges. These issues are clearly dealt with by geriatricians and nephrologists. Improvements in care and advancing clinical knowledge will enable us to delineate more clearly those changes that are due to aging as opposed to those changes due to disease. This book provides an important step in further clarifying and quantifying the differences between an aging and a diseased kidney.