This is not an outline or an all encompassing book. It is a book for students that want to learn the major concepts in the field with enough detail to feel that they can connect the dots. I especially hope this book will help learners bridge the gap between the science of medicine and clinical medicine. It is the spiritual successor of 25 years of teaching renal physiology, fluid and electrolytes, and acid-base to students, residents and fellows. Each chapter is followed by several questions and detailed answers.