Book excerpt: This book sheds new light on the physiology, molecular biology and pathophysiology of epithelial ion channels and transporters. It combines the basic cellular models and functions by means of a compelling clinical perspective, addressing aspects from the laboratory bench to the bedside. The individual chapters, written by leading scientists and clinicians, explore specific ion channels and transporters located in the epithelial tissues of the kidney, intestine, pancreas and respiratory tract, all of which play a crucial part in maintaining homeostasis. Further topics include the fundamentals of epithelial transport; mathematical modeling of ion transport; cell volume regulation; membrane protein folding and trafficking; transepithelial transport functions; and lastly, a discussion of transport proteins as potential pharmacological targets with a focus on the pharmacology of potassium channels.