This volume was designed as a text for medical students, house officers, and even clinicians. It deals with the most common problems in nephrology, providing new insight into how to improve clinical skills. A comprehensive overview of renal physiology and electrolyte disorders lays the groundwork for a clear presentation of the pathophysiological principles that underlie these disorders and a step-by-step presentation of the mechanisms behind the signs and symptoms of kidney failure. The origins of this book can be traced to the teaching of a Renal Pathophysiology course at the Washington University School of Medicine, beginning in the mid-1960s. When changes in the medical school curriculum took place in the early 1970s, an effort was made to synthesize the minimum core curriculum for sophomore medical students, and the distillation of "essential material" to be covered in the area of renal pathophysiology led to the development of the first edition of a renal syllabus. This syllabus has been used in our department since 1974, and, following some of the recommendations and critiques of students and faculty, it has been entirely reworked many times to improve its effectiveness and value. This book is a direct extension of that syllabus, integrated with contri- butions from faculty members in our Renal Division, and expanded to include a section on therapy in most chapters. It is our hope that this format will serve the needs of not only sophomore and senior medical students, but also house officers, nephrology fellows, and clinicians.