The aquaporin field has matured at an exceptionally fast pace and we are at the verge to develop serious strategies to therapeutically modulate aquaporin function directly or via regulatory networks. Key prerequisites are available today: i. a considerable (and growing) number of aquaporin crystal structures for the rational design of inhibitory molecules, ii. elaborate molecular dynamics simulation techniques for theoretical analyses of selectivity mechanisms and docking experiments, iii. comprehensive data on aquaporin immunohistochemistry, iv. aquaporin knockout animals for physiological studies, and v. assay systems for compound library screenings. The structure of this volume on aquaporins follows the points laid out above and thus covers the developments from basic research to potential pharmacological use. Situated between pharmacology textbooks and recent scientific papers this book provides a timely overview for readers from the fundamental as well as the applied disciplines.