The main purpose of this book is to provide in-depth presentation of physical techniques for measuring water transport and their applications to a variety of biological membranes, from model membrane systems to cell membranes, and then from isolated cells to multicellular barrier systems, such as epithelia or even whole organisms. This survey of water transport in such a broad range of membrane systems will hopefully contribute to understanding of the structure-function relationships and molecular mechanisms of water permeation. Moreover, the description of various techniques, together with a review of literature will enable the readers to assess whether a technique would be useful in helping to solve his or her particular problem of research and will also expand their competence in these techniques. The book consists of two volumes.