This text elucidates one of the most difficult topics in clinical medicine. The underlying premise of the text is that clinical disturbances of acid-base and electrolyte balance are most effectively managed by understanding the basic principles of renal and electrolyte physiology. Toward that end the text begins with a review of normal renal function, extrarenal fluids and regulatory processes. Next, the major disorders of acid-base and electrolyte balance are reviewed with concise summaries of etiology, symptoms, diagnosis and treatment. Discussion of pathophysiology of each disorder is cross-referenced to earlier chapters to effectively tie together basic principles and clinical applications.